Environment, Ecology and Biodiversity

139 questions

All types139 Multiple choice73 Multiple select24 Matching26 Ordering16

Match List-I (Atmospheric Pollutants / Synthetic Compounds) with List-II (Regulatory Frameworks and Environmental Characteristics) and select the correct matching pairs.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Perfluorocarbons (PFCs) match with extremely persistent synthetic GHGs emitted primarily during primary aluminum smelting. Stratospheric Halons match with bromine-containing compounds possessing significantly higher ODP per molecule than standard CFCs. Hydrofluorocarbons (HFCs) match with phase-down under the Kigali Amendment due to high GWP despite zero ODP. Nitrogen Trifluoride (

NF_3

) matches with addition to the Kyoto Protocol basket under the Doha Amendment.

Perfluorocarbons (PFCs) are extremely long-lived synthetic greenhouse gases originating from aluminum smelting. Stratospheric Halons contain bromine, which exhibits much higher Ozone Depleting Potential per molecule than chlorine in CFCs. Hydrofluorocarbons (HFCs) have zero Ozone Depleting Potential but high Global Warming Potential, leading to their regulation under the Kigali Amendment. Nitrogen Trifluoride (

NF_3

) was added to the Kyoto Protocol greenhouse gas list during the Doha Amendment.

Step-by-Step Solution

Analyze the industrial sources and chemical persistence of Perfluorocarbons (PFCs).

PFCs (

CF_4

C_2F_6

) are generated as inadvertent byproducts during aluminum smelting (anode effect) and microelectronics etching, characterized by extreme atmospheric lifetimes (up to 50,000 years).

Links PFCs to aluminum smelting emissions and extreme atmospheric longevity.

Evaluate the atmospheric ozone destruction potential of Halons.

Halons carry bromine atoms (

Br

), which participate in catalytic ozone destruction cycles that are substantially more destructive per atom than the chlorine cycles of CFCs.

Establishes why Halons exhibit higher ODP values compared to standard CFCs.

Examine the international legal regime covering Hydrofluorocarbons (HFCs).

While HFCs do not harm the ozone layer (zero ODP), they are potent greenhouse gases. The 2016 Kigali Amendment legally amended the Montreal Protocol to include HFC phase-down schedules.

Connects HFCs with zero ODP and the Kigali Amendment phase-down framework.

Trace the history of greenhouse gas listings under the Kyoto Protocol for Nitrogen Trifluoride (

NF_3

The original 1997 Kyoto Protocol covered six gases (

CO_2

CH_4

N_2O

, HFCs, PFCs,

SF_6

). Nitrogen Trifluoride (

NF_3

) was added as the seventh gas under the 2012 Doha Amendment for the second commitment period (2013–2020).

Pairs

NF_3

with the Doha Amendment expansion of the Kyoto Protocol GHG basket.

Key Concept

Chemical mechanisms of ozone depleting substances, greenhouse gas profiles, and global climate governance treaties

Question 42Question →

Hydrofluorocarbons (HFCs) were introduced as non-ozone-depleting alternatives to Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs). Which of the following statements correctly explains why HFCs are being phased down globally under the 2016 Kigali Amendment to the Montreal Protocol?

They have high Global Warming Potentials (GWPs), acting as powerful greenhouse gases that significantly contribute to global warming.

They breakdown rapidly in the stratosphere to release active chlorine radicals that catalyze catalytic ozone destruction cycles.

They react directly with tropospheric nitrogen oxides (

NO_x

) to form toxic ground-level smog and secondary organic aerosols.

They freeze at ambient stratospheric temperatures to create Polar Stratospheric Clouds (PSCs) that accelerate ozone hole formation.

Show answer & explanation

Answer: They have high Global Warming Potentials (GWPs), acting as powerful greenhouse gases that significantly contribute to global warming.

Answer

Hydrofluorocarbons are being phased down under the Kigali Amendment because they possess high Global Warming Potentials (GWPs) and act as potent greenhouse gases.

The statement identifying high Global Warming Potentials (GWPs) is correct. While Hydrofluorocarbons do not damage the stratospheric ozone layer (ODP = 0), they are extremely potent greenhouse gases capable of trapping significant heat in the atmosphere. The 2016 Kigali Amendment to the Montreal Protocol was specifically designed to phase down HFCs to prevent additional global temperature rise.

Step-by-Step Solution

Identify the chemical nature and ozone depletion potential of HFCs

HFCs contain hydrogen, fluorine, and carbon, but no chlorine or bromine atoms. As a result, their Ozone Depletion Potential (ODP) is virtually zero.

Understanding why HFCs replaced CFCs helps differentiate their impact on ozone depletion versus global warming.

Analyze the environmental threat posed by HFCs

Despite having zero ODP, HFCs are potent greenhouse gases with Global Warming Potentials (GWPs) ranging from hundreds to over 10,000 times that of carbon dioxide (

CO_2

High GWP compounds trap thermal infrared radiation efficiently, accelerating planetary warming.

Connect the environmental impact to the Kigali Amendment objective

The 2016 Kigali Amendment legally amended the Montreal Protocol to mandate a global phase-down of HFC production and consumption to avoid up to 0.5 °C of warming by the end of the century.

The amendment expanded the scope of the Montreal Protocol from strictly protecting stratospheric ozone to mitigating climate change caused by HFC substitutes.

Key Concept

Kigali Amendment and Global Warming Potential of HFCs

Question 43Question →

In climate science and global environmental policy under the Intergovernmental Panel on Climate Change (IPCC) frameworks, metrics such as Global Warming Potential (GWP) and Global Temperature Change Potential (GTP) are used to compare the climate impacts of non- $CO_2$ greenhouse gases. Which of the following statements accurately distinguishes Global Warming Potential (GWP) from Global Temperature Change Potential (GTP)?

GWP measures instantaneous radiative forcing per unit mass at a specific future date, whereas GTP calculates the cumulative thermal energy trapped over an entire time horizon.

GWP measures the integrated radiative forcing of a pulse emission over a chosen time horizon relative to

CO_2

, whereas GTP measures the change in global mean surface temperature at a chosen point in time relative to

CO_2

For short-lived climate pollutants such as methane (

CH_4

), the 100-year GTP value is consistently higher than its 100-year GWP value.

Both GWP and GTP assume an infinite atmospheric residence time for carbon dioxide (

CO_2

) without incorporating carbon cycle decay models.

Show answer & explanation

Answer: GWP measures the integrated radiative forcing of a pulse emission over a chosen time horizon relative to $CO_2$ , whereas GTP measures the change in global mean surface temperature at a chosen point in time relative to $CO_2$ .

Answer

Global Warming Potential (GWP) integrates radiative forcing over a designated time horizon relative to carbon dioxide, whereas Global Temperature Change Potential (GTP) calculates the relative change in global mean surface temperature at a specific future point in time.

The correct answer accurately states the physical basis of both IPCC climate metrics: Global Warming Potential (GWP) integrates total radiative forcing (energy absorbed) over a time window, whereas Global Temperature Change Potential (GTP) evaluates the resulting global surface temperature change at a specific point in time relative to reference carbon dioxide emissions.

Step-by-Step Solution

Analyze the definition of Global Warming Potential (GWP)

GWP is defined as the time-integrated radiative forcing caused by a pulse emission of 1 kg of a trace gas relative to 1 kg of reference gas carbon dioxide (

CO_2

) over a specified time horizon

TH

(e.g.,

GWP_{100} = \frac{\int_{0}^{TH} RF_i(t) dt}{\int_{0}^{TH} RF_{CO_2}(t) dt}

Understanding GWP as a cumulative energy metric is essential for differentiating it from temperature-endpoint metrics.

Analyze the definition of Global Temperature Change Potential (GTP)

GTP is defined as the change in global mean surface temperature at a chosen point in time

t

relative to the temperature change caused by

CO_2

(

GTP(t) = \frac{\Delta T_i(t)}{\Delta T_{CO_2}(t)}

GTP measures an endpoint climate outcome (surface warming) rather than cumulative energy input.

Compare GWP and GTP behavior for short-lived climate pollutants (SLCPs) like methane (

CH_4

)

Because

CH_4

has a relatively short atmospheric lifetime (~11.8 years), its instantaneous radiative forcing rapidly diminishes after pulse emission. Thus, cumulative integrated forcing over 100 years (

GWP_{100} \approx 28

) yields a higher numerical value than its point-in-time surface temperature impact at year 100 (

GTP_{100} \approx 4

This physical behavior confirms that statement claiming higher GTP values for short-lived pollutants is erroneous.

Key Concept

Atmospheric Climate Metrics: Radiative Forcing (GWP) vs Surface Temperature Response (GTP)

Estimated Time:3m 0s

Question 44Question →

Match List-I (International Conventions/Protocols) with List-II (Specific Key Regulatory Mechanisms) and identify the correct pairs according to their primary legal mandates under international environmental law.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Cartagena Protocol corresponds to Advanced Informed Agreement (AIA) procedure for Living Modified Organisms (LMOs); Rotterdam Convention corresponds to Prior Informed Consent (PIC) procedure for hazardous trade chemicals; Nagoya Protocol corresponds to ABS Clearing-House mechanism for genetic resources; Minamata Convention corresponds to phased prohibition of primary mining and regulation of artisanal small-scale gold mining.

Each international environmental agreement targets a distinct ecological concern: Cartagena Protocol handles Living Modified Organisms via the Advanced Informed Agreement (AIA) procedure; Rotterdam Convention regulates trade of hazardous chemicals using the Prior Informed Consent (PIC) mechanism; Nagoya Protocol regulates Access and Benefit-Sharing (ABS) of genetic resources via the ABS Clearing-House; and Minamata Convention specifically bans primary mercury mining and regulates releases from artisanal gold mining.

Step-by-Step Solution

Analyze Cartagena Protocol mandate

Identified as a supplementary agreement to the Convention on Biological Diversity (CBD) regulating Living Modified Organisms via the Advanced Informed Agreement (AIA) procedure.

Cartagena addresses biotechnology safety and environmental risks during LMO transboundary movements.

Analyze Rotterdam Convention mandate

Identified as the treaty establishing the legally binding Prior Informed Consent (PIC) procedure for hazardous trade chemicals.

Rotterdam focuses on trade transparency and country consent regarding toxic chemicals and pesticides.

Analyze Nagoya Protocol mandate

Identified as the treaty implementing Access and Benefit-Sharing (ABS) and establishing the ABS Clearing-House mechanism.

Nagoya governs equitable sharing of benefits from genetic resources and traditional knowledge utilization.

Analyze Minamata Convention mandate

Identified as the treaty targeting elemental mercury and mercury compounds, banning primary mining and controlling emissions from artisanal gold mining.

Minamata aims to protect human health and the environment from anthropogenic emissions of mercury.

Key Concept

Core Mechanisms and Specific Mandates of Major International Environmental Treaties

Question 45Question →

Which of the following statements regarding the physical and chemical dynamics of global warming and atmospheric ozone are correct?

Select all that apply

Stratospheric ozone absorbs harmful ultraviolet-B (

UV\text{-}B

) radiation, preventing the majority of high-energy solar radiation from reaching the Earth's surface.

Carbon dioxide (

CO_2

) possesses a significantly higher Global Warming Potential (

GWP

) than methane (

CH_4

) over a 100-year time horizon.

Nitrous oxide (

N_2O

) acts both as a greenhouse gas in the troposphere and as a major catalyst for ozone depletion in the stratosphere.

Tropospheric ozone acts primarily as a radiative cooling agent by scattering incoming shortwave solar rays back into space.

Show answer & explanation

Answer: Stratospheric ozone absorbs harmful ultraviolet-B ( $UV\text{-}B$ ) radiation, preventing the majority of high-energy solar radiation from reaching the Earth's surface.; Nitrous oxide ( $N_2O$ ) acts both as a greenhouse gas in the troposphere and as a major catalyst for ozone depletion in the stratosphere.

Answer

The statements confirming that stratospheric ozone absorbs harmful UV-B radiation and that nitrous oxide acts as both a greenhouse gas and an ozone-depleting agent are correct.

The statement regarding stratospheric ozone is correct because the ozone layer shields the biosphere from harmful UV-B rays. The statement regarding nitrous oxide is also correct because N2O is both a powerful greenhouse gas in the troposphere and the single largest ozone-depleting substance emission in the 21st century.

Step-by-Step Solution

Evaluate the statement concerning stratospheric ozone absorption

Stratospheric ozone absorbs high-energy solar UV-B radiation (

280\text{--}315\text{ nm}

), which is vital for preventing radiation damage on Earth.

This statement accurately reflects the protective role of ozone in the stratosphere.

Compare Global Warming Potentials of carbon dioxide and methane

CO_2

is the reference gas with a

GWP = 1

, whereas

CH_4

has a 100-year

GWP

of around

28\text{--}36

The statement incorrectly claims

CO_2

has a higher

GWP

than

CH_4

Analyze the dual atmospheric impacts of nitrous oxide

N_2O

traps heat in the troposphere (

GWP \approx 273

) and decomposes into

NO_x

radicals in the stratosphere, catalytically destroying

O_3

This statement correctly describes both the climate warming and ozone depletion effects of nitrous oxide.

Examine the radiative property of tropospheric ozone

Tropospheric ozone is a key greenhouse gas that absorbs outgoing longwave infrared radiation, warming the lower atmosphere.

The statement incorrectly describes tropospheric ozone as a cooling agent that scatters solar rays.

Key Concept

Dual roles of atmospheric gases in climate forcing and stratospheric ozone chemistry

Question 46Question →

With reference to the chemical mechanism of stratospheric ozone depletion over Antarctica, consider the following statements:

1. Polar Stratospheric Clouds (PSCs) provide catalytic surfaces for heterogeneous reactions that convert inactive chlorine reservoirs ( $HCl$ and $ClONO_2$ ) into reactive chlorine species.
2. The catalytic destruction of ozone molecules by active chlorine free radicals occurs rapidly during the dark polar winter.
3. The polar vortex plays a crucial role by confining cold air over Antarctica, preventing mixing with mid-latitude air masses and maintaining low temperatures required for PSC formation.

Which of the statements given above is/are correct?

1 and 3 only

1 and 2 only

2 and 3 only

1, 2 and 3

Show answer & explanation

Answer: 1 and 3 only

Answer

1 and 3 only

The correct answer states that 1 and 3 only are true. PSC surfaces enable the chemical transformation of reservoir compounds into chlorine gas (

Cl_2

). The Antarctic polar vortex isolates cold polar air to maintain temperatures under

-78^\circ\text{C}

. However, active ozone destruction requires sunlight to photolyze

Cl_2

into free chlorine radicals, which happens during Antarctic spring rather than dark polar winter.

Step-by-Step Solution

Evaluate Statement 1 regarding Polar Stratospheric Clouds (PSCs)

Statement 1 is TRUE. PSCs formed in extremely cold temperatures (below

-78^\circ\text{C}

) provide ice particle surfaces for heterogeneous reactions converting stable reservoir species (

HCl

and

ClONO_2

) into photolytically active forms like

Cl_2

and

HOCl

Heterogeneous chemistry on PSC surfaces is a fundamental precursor step to ozone hole formation.

Evaluate Statement 2 regarding timing of ozone destruction

Statement 2 is FALSE. During dark winter, molecular chlorine (

Cl_2

) accumulates. Photolysis (splitting of

Cl_2

into reactive

Cl^\bullet

radicals by solar UV radiation) requires sunlight, which occurs when spring arrives (September-October). Rapid catalytic ozone destruction occurs during early spring, not during polar winter.

Chlorine catalytic cycles require photon absorption (

h\nu

) from solar ultraviolet radiation.

Evaluate Statement 3 regarding the polar vortex

Statement 3 is TRUE. A strong ring of circulating wind (polar vortex) seals polar stratospheric air, preventing warmer, ozone-rich air from mid-latitudes from entering and sustaining ultra-cold conditions necessary for PSC stability.

Isolation by the polar vortex maintains environmental conditions necessary for PSC persistence.

Key Concept

Heterogeneous chemistry on Polar Stratospheric Clouds and photochemical destruction of stratospheric ozone by chlorine radicals during Antarctic spring.

Question 47Question →

Match the international agreements and atmospheric phenomena related to climate change and ozone layer depletion in List-I with their primary descriptions or objectives in List-II:

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct matches are: Kigali Amendment pairs with the legally binding phase-down of high GWP HFCs; Kyoto Protocol pairs with international commitments to limit greenhouse gas emissions; Stratospheric Ozone pairs with the atmospheric shield absorbing harmful UV-B radiation; and Tropospheric Ozone pairs with the secondary air pollutant formed via photochemical reactions.

The Kigali Amendment explicitly targets the phase-down of Hydrofluorocarbons (HFCs) due to their high climate-warming impact. The Kyoto Protocol establishes binding emission targets for major greenhouse gases. Stratospheric ozone functions as a protective shield against ultraviolet-B radiation, whereas tropospheric ozone operates as a secondary air pollutant and short-lived climate force.

Step-by-Step Solution

Identify the primary mechanism of the Kigali Amendment

It amends the Montreal Protocol to reduce HFC consumption due to high Global Warming Potential.

HFCs replaced CFCs to protect ozone, but were identified as potent climate-warming gases.

Identify the main purpose of the Kyoto Protocol

It focuses on legally binding targets to reduce greenhouse gases responsible for global warming.

Adopted in 1997 under UNFCCC framework specifically targeting GHG emission control.

Distinguish between Stratospheric and Tropospheric Ozone

Stratospheric ozone is beneficial ('good ozone') shielding against solar UV-B, while tropospheric ozone is ground-level smog ('bad ozone') and a greenhouse gas.

Location determines whether ozone acts as a protective filter or an environmental pollutant.

Key Concept

Climate treaties, global warming mitigation, and dual roles of stratospheric versus tropospheric ozone

Estimated Time:1m 15s

Question 48Question →

Consider the following statements regarding international environmental conventions and protocols:

1. The Cartagena Protocol on Biosafety operates under the framework of the Convention on Biological Diversity (CBD) to ensure the safe handling, transport, and use of Living Modified Organisms (LMOs).
2. The Rotterdam Convention provides a legally binding Prior Informed Consent (PIC) procedure for facilitating information exchange regarding specific hazardous chemicals and pesticides in international trade.
3. The Bonn Convention (CMS) establishes an appendix-based export and import permitting framework to regulate commercial international trade in endangered species.

Which of the statements given above are correct?

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

Show answer & explanation

Answer: 1 and 2 only

Answer

1 and 2 only

Statements 1 and 2 are factual and correctly describe the scope of the Cartagena Protocol (LMO safety under CBD) and the Rotterdam Convention (PIC procedure for hazardous chemicals). Statement 3 is false because international trade regulation via permit appendices is governed by CITES, whereas the Bonn Convention focuses on migratory species across habitats.

Step-by-Step Solution

Evaluate Statement 1 regarding the Cartagena Protocol

Statement 1 is correct. The Cartagena Protocol on Biosafety was adopted under the Convention on Biological Diversity (CBD) to protect biological diversity from potential risks posed by Living Modified Organisms (LMOs) resulting from modern biotechnology.

Verifying the governing treaty framework and key focus organism of the protocol.

Evaluate Statement 2 regarding the Rotterdam Convention

Statement 2 is correct. The Rotterdam Convention governs the Prior Informed Consent (PIC) procedure for certain hazardous chemicals and pesticides in international trade to promote shared responsibility and cooperative efforts.

Verifying chemical trade international mechanisms.

Evaluate Statement 3 regarding the Bonn Convention

Statement 3 is incorrect. The regulation of commercial trade in endangered species via Appendix I, II, and III permits is executed under CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). The Bonn Convention (Convention on the Conservation of Migratory Species of Wild Animals, or CMS) aims to conserve terrestrial, aquatic, and avian migratory species throughout their range.

Distinguishing trade regulation instruments (CITES) from habitat/migratory species conservation treaties (Bonn Convention).

Key Concept

Core mandates and regulatory mechanisms of major global environmental treaties (CBD Cartagena Protocol, Rotterdam Convention, CITES vs Bonn Convention).

Question 49Question →

Arrange the following major international environmental conventions and protocols in chronological order of their adoption, from the earliest to the latest:

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological sequence of adoption from earliest to latest is: Ramsar Convention (1971) → Montreal Protocol (1987) → Kyoto Protocol (1997) → Minamata Convention on Mercury (2013).

The correct sequence arranges the treaties according to their official adoption dates: Ramsar Convention (1971), Montreal Protocol (1987), Kyoto Protocol (1997), and Minamata Convention on Mercury (2013).

Step-by-Step Solution

Determine the adoption year for each international treaty

Ramsar Convention: 1971; Montreal Protocol: 1987; Kyoto Protocol: 1997; Minamata Convention: 2013.

Identifying exact adoption dates is essential for accurate historical sequencing.

Sort the treaties chronologically by year of adoption

1971 (Ramsar) comes before 1987 (Montreal), followed by 1997 (Kyoto), and lastly 2013 (Minamata).

Arranging the years in ascending numerical order yields the correct temporal progression.

Key Concept

Chronological Timeline of Key Environmental Conventions and Protocols

Estimated Time:1m 30s

Question 50Question →

Match the environmental statutory bodies in List-I with their corresponding legal provisions and enacting statutes in List-II:

Click a left item, then click its matching right item

Show answer & explanation

Answer

Central Ground Water Authority matches with Section 3(3) of the Environment (Protection) Act, 1986; Central Pollution Control Board matches with Section 3 of the Water (Prevention and Control of Pollution) Act, 1974; National Biodiversity Authority matches with Section 8 of the Biological Diversity Act, 2002; and National Board for Wildlife matches with Section 5A of the Wild Life (Protection) Act, 1972.

Each environmental body is mapped to its exact statutory section and parent legislation: Central Ground Water Authority to Section 3(3) of the Environment (Protection) Act 1986, Central Pollution Control Board to Section 3 of the Water Act 1974, National Biodiversity Authority to Section 8 of the Biological Diversity Act 2002, and National Board for Wildlife to Section 5A of the Wild Life (Protection) Act 1972.

Step-by-Step Solution

Determine the statutory origin of the Central Ground Water Authority.

Constituted under Section 3(3) of the Environment (Protection) Act, 1986.

Although CGWA regulates groundwater, it derives its legal authority from the Environment (Protection) Act, 1986 rather than the Water Act.

Identify the parent act establishing the Central Pollution Control Board.

Established under Section 3 of the Water (Prevention and Control of Pollution) Act, 1974.

CPCB was created under the Water Act of 1974 and later delegated powers under the Air (Prevention and Control of Pollution) Act, 1981.

Identify the statutory backing of the National Biodiversity Authority.

Established under Section 8 of the Biological Diversity Act, 2002.

NBA was set up in 2003 at Chennai to implement India's Biological Diversity Act, 2002.

Determine the legal origin of the National Board for Wildlife.

Constituted under Section 5A of the Wild Life (Protection) Act, 1972.

The National Board for Wildlife replaced the non-statutory Indian Board for Wildlife via the 2002 amendment inserting Section 5A into the 1972 Act.

Key Concept

Statutory origins and legal provisions of national environmental bodies in India

Question 51Question →

Consider the following statements regarding major international multilateral environmental agreements:

1. The Rotterdam Convention establishes a Prior Informed Consent (PIC) procedure for certain hazardous chemicals and pesticides traded internationally to facilitate information exchange among member nations.
2. The Stockholm Convention regulates Persistent Organic Pollutants (POPs) by categorizing targeted chemicals into Annex A (Elimination), Annex B (Restriction), and Annex C (Unintentional Production).
3. The Kigali Amendment to the Montreal Protocol aims for the global phasedown of Hydrofluorocarbons (HFCs), which have high global warming potential despite being non-ozone-depleting substances.

Which of the statements given above are correct?

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

Show answer & explanation

Answer: 1, 2 and 3

Answer

Statements 1, 2, and 3 are all correct.

All three provided statements correctly detail the key operational instruments of global environmental law: the Rotterdam Convention utilizes the Prior Informed Consent (PIC) procedure for hazardous chemicals; the Stockholm Convention organizes POPs management across Annexes A, B, and C; and the Kigali Amendment expands the Montreal Protocol framework to address climate change by phasing down non-ozone-depleting HFCs.

Step-by-Step Solution

Analyze Statement 1 regarding the Rotterdam Convention

The Rotterdam Convention (adopted in 1998) enforces the Prior Informed Consent (PIC) procedure for hazardous chemicals and pesticides, allowing importing countries to decide which chemicals they accept.

Verifying the core mandate and tool of the Rotterdam Convention.

Analyze Statement 2 regarding the Stockholm Convention

The Stockholm Convention (adopted in 2001) manages Persistent Organic Pollutants using three main annexes: Annex A for elimination, Annex B for restriction (e.g., DDT for malaria control), and Annex C for minimizing unintentional releases (e.g., dioxins and furans).

Verifying the legal structure and annex classification of POPs.

Analyze Statement 3 regarding the Kigali Amendment

The Kigali Amendment (2016) extended the scope of the 1987 Montreal Protocol to phase down Hydrofluorocarbons (HFCs), which replaced ozone-depleting substances but act as potent greenhouse gases.

Verifying the distinction between ozone-depleting substances and greenhouse gas targets under Montreal Protocol amendments.

Key Concept

Core mechanisms and scopes of international hazardous chemicals, POPs, and climate/ozone protection treaties

Question 52Question →

Short-lived climate pollutants (SLCPs) contribute significantly to global warming alongside long-lived greenhouse gases. Regarding the atmospheric behavior, warming mechanisms, and environmental impacts of climate forcing agents, which of the following statements are correct?

Select all that apply

Black carbon accelerates glacial melting by reducing surface albedo when deposited on ice and snow, while also absorbing direct solar radiation in the atmosphere.

Hydrofluorocarbons (HFCs) contribute significantly to stratospheric ozone depletion in addition to having high global warming potential.

Tropospheric ozone acts as a greenhouse gas and is formed primarily through photochemical reactions involving nitrogen oxides (

NO_x

) and volatile organic compounds (

VOCs

Sulfur hexafluoride (

SF_6

) is classified as a short-lived climate pollutant due to its rapid photochemical breakdown in the lower atmosphere.

Show answer & explanation

Answer: Black carbon accelerates glacial melting by reducing surface albedo when deposited on ice and snow, while also absorbing direct solar radiation in the atmosphere.; Tropospheric ozone acts as a greenhouse gas and is formed primarily through photochemical reactions involving nitrogen oxides ( $NO_x$ ) and volatile organic compounds ( $VOCs$ ).

Answer

The correct statements are that black carbon accelerates glacial melting by reducing surface albedo and absorbing solar radiation, and tropospheric ozone acts as a greenhouse gas formed photochemically from

NO_x

and VOC precursors.

Black carbon deposits darken snow and ice, lowering surface albedo and accelerating thermal energy absorption, while directly heating the surrounding atmosphere. Tropospheric ozone is a secondary pollutant formed via sunlight-driven reactions between

NO_x

and volatile organic compounds (

VOCs

), functioning as a major radiative forcing agent in the lower atmosphere.

Step-by-Step Solution

Analyze the impact and physical properties of black carbon.

Black carbon absorbs solar radiation and reduces snow albedo, accelerating melting.

Black carbon particles absorb sunlight directly and darken reflective snow cover.

Evaluate the chemical composition and ozone-depleting capability of hydrofluorocarbons (HFCs).

HFCs do not deplete stratospheric ozone because they lack chlorine and bromine.

Ozone depletion mechanisms require catalytic halogen radicals like

Cl^\bullet

Br^\bullet

, which HFCs do not carry.

Assess the origin and climate role of tropospheric ozone.

Tropospheric ozone is a key short-lived climate pollutant formed from

NO_x

and VOCs.

Unlike stratospheric ozone, tropospheric ozone acts as a greenhouse gas and is synthesized photochemically from precursor gases.

Examine the atmospheric lifetime of sulfur hexafluoride (

SF_6

SF_6

is one of the most persistent greenhouse gases, not a short-lived pollutant.

SF_6

has an atmospheric lifetime of approximately 3,200 years.

Key Concept

Short-Lived Climate Pollutants (SLCPs) and Atmospheric Forcing Mechanisms

Question 53Question →

With reference to national environmental legislation and statutory regulatory framework in India, consider the following statements:

1. The Central Ground Water Authority (CGWA) was statutorily constituted under sub-section (3) of Section 3 of the Environment (Protection) Act, 1986.
2. The State Board for Wildlife (SBWL) is statutorily chaired by the Chief Minister of the concerned State under the Wildlife (Protection) Act, 1972.
3. The National Green Tribunal (NGT) is strictly bound by the procedural rules laid down under the Code of Civil Procedure, 1908, while adjudicating environmental disputes.

Which of the statements given above is/are correct?

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

Show answer & explanation

Answer: 1 and 2 only

Answer

1 and 2 only

The correct combination includes statements 1 and 2 only. Central Ground Water Authority (CGWA) was created under Section 3(3) of the Environment (Protection) Act, 1986. The State Board for Wildlife is chaired ex-officio by the Chief Minister of the respective state under the Wildlife (Protection) Act, 1972. Statement 3 is incorrect because Section 19 of the NGT Act, 2010 specifically exempts NGT from being bound by the Code of Civil Procedure, 1908.

Step-by-Step Solution

Evaluate Statement 1 regarding the statutory origin of the Central Ground Water Authority (CGWA).

Statement 1 is CORRECT.

CGWA was constituted under Section 3(3) of the Environment (Protection) Act, 1986, to regulate and control ground water development and management in India.

Evaluate Statement 2 regarding the chairmanship of the State Board for Wildlife (SBWL).

Statement 2 is CORRECT.

Section 6 of the Wildlife (Protection) Act, 1972 provides for the constitution of the State Board for Wildlife, with the Chief Minister of the State (or Administrator in Union Territories) as its Chairperson.

Evaluate Statement 3 regarding the procedural binding of the National Green Tribunal (NGT).

Statement 3 is INCORRECT.

According to Section 19(1) of the National Green Tribunal Act, 2010, the Tribunal shall not be bound by the procedure laid down by the Code of Civil Procedure, 1908, but shall be guided by the principles of natural justice.

Key Concept

Statutory provisions and authority origins under major Indian environmental laws (Environment Protection Act 1986, Wildlife Protection Act 1972, NGT Act 2010)

Question 54Question →

Match List-I (International Environmental Agreement/Protocol) with List-II (Core Regulatory Mechanism / Primary Focus) and select the correct matching pairs.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct matches pair the Rotterdam Convention with the Prior Informed Consent procedure, the Stockholm Convention with Persistent Organic Pollutants regulation, the Nagoya Protocol with Access and Benefit-Sharing of genetic resources, and the Minamata Convention with mercury emissions control.

Each international agreement has a distinct legal scope: Rotterdam regulates international trade of hazardous chemicals via the Prior Informed Consent (PIC) mechanism; Stockholm aims to eliminate Persistent Organic Pollutants (POPs); Nagoya establishes rules for Access and Benefit-Sharing (ABS) of genetic resources under CBD; and Minamata addresses global mercury pollution and emissions.

Step-by-Step Solution

Identify the primary mechanism of the Rotterdam Convention

Rotterdam governs hazardous chemicals in global trade via the Prior Informed Consent (PIC) mechanism.

It ensures importing countries are informed about incoming hazardous substances before shipment.

Identify the core mandate of the Stockholm Convention

Stockholm focuses on eliminating or strictly limiting Persistent Organic Pollutants (POPs), including the initial 'dirty dozen'.

POPs persist in the environment, bioaccumulate through the food web, and pose global risks.

Identify the target scope of the Nagoya Protocol

Nagoya is a supplementary treaty under the CBD focused specifically on Access to Genetic Resources and Benefit-Sharing (ABS).

It operationalizes one of the three core objectives of the Convention on Biological Diversity.

Identify the regulatory focus of the Minamata Convention

Minamata is dedicated to controlling and phasing out industrial mercury usage, emissions, and waste.

Named after Minamata, Japan, where severe mercury poisoning occurred, the treaty addresses toxic heavy metal pollution.

Key Concept

Regulatory Focus and Mandates of Multilateral Environmental Agreements

Question 55Question →

During stratospheric ozone layer depletion, chlorofluorocarbons (CFCs) release free chlorine radicals ( $\text{Cl}^\bullet$ ) upon photolysis by solar ultraviolet radiation. Which of the following statements correctly describes how a chlorine radical acts catalytically to destroy ozone molecules without being consumed in the net reaction?

It reacts with an ozone molecule (

\text{O}_3

) to form chlorine monoxide (

\text{ClO}

) and oxygen (

\text{O}_2

), and is regenerated when

\text{ClO}

reacts with a free oxygen atom (

\text{O}

It absorbs terrestrial longwave infrared radiation, raising local stratospheric temperatures high enough to induce thermal dissociation of ozone.

It reacts irreversibly with stratospheric moisture to produce hydrochloric acid (

\text{HCl}

), consuming one molecule of ozone per chlorine atom in a single stoichiometric reaction.

It drives the photolytic oxidation of atmospheric nitrogen into nitrous oxide (

\text{N}_2\text{O}

), which subsequently blocks the formation of oxygen radicals.

Show answer & explanation

Answer: It reacts with an ozone molecule ( $\text{O}_3$ ) to form chlorine monoxide ( $\text{ClO}$ ) and oxygen ( $\text{O}_2$ ), and is regenerated when $\text{ClO}$ reacts with a free oxygen atom ( $\text{O}$ ).

Answer

A chlorine radical destroys ozone by reacting with an ozone molecule (

\text{O}_3

) to produce chlorine monoxide (

\text{ClO}

) and molecular oxygen (

\text{O}_2

). It is subsequently regenerated when

\text{ClO}

reacts with a free atomic oxygen atom (

\text{O}

), allowing the cycle to repeat.

The catalytic cycle of ozone depletion by chlorine free radicals consists of two key elementary reactions:

\text{Cl}^\bullet + \text{O}_3 \rightarrow \text{ClO}^\bullet + \text{O}_2

followed by

\text{ClO}^\bullet + \text{O} \rightarrow \text{Cl}^\bullet + \text{O}_2

. Because the free chlorine radical (

\text{Cl}^\bullet

) is regenerated in the second step, it is not consumed in the overall reaction (

\text{O}_3 + \text{O} \rightarrow 2\text{O}_2

), enabling a single chlorine radical to destroy up to

10^5

ozone molecules in the stratosphere.

Step-by-Step Solution

Identify the primary reaction of the chlorine radical with ozone.

\text{Cl}^\bullet + \text{O}_3 \rightarrow \text{ClO}^\bullet + \text{O}_2

The chlorine radical abstracts an oxygen atom from ozone, creating chlorine monoxide.

Determine the regeneration step of the catalyst.

\text{ClO}^\bullet + \text{O} \rightarrow \text{Cl}^\bullet + \text{O}_2

Chlorine monoxide reacts with atomic oxygen in the stratosphere, liberating the chlorine radical.

Sum the two steps to get the net chemical equation.

Net reaction:

\text{O}_3 + \text{O} \rightarrow 2\text{O}_2

The chlorine radical (

\text{Cl}^\bullet

) acts purely as a catalyst and does not appear in the net reaction.

Key Concept

Catalytic destruction of stratospheric ozone by halogen radicals

Question 56Question →

Match the atmospheric gases and pollutants listed in List-I with their primary environmental characteristic or atmospheric behavior described in List-II:

Click a left item, then click its matching right item

Show answer & explanation

Answer

Sulfur Hexafluoride (

SF_6

) matches with the synthetic greenhouse gas exhibiting the highest 100-year GWP (~23,500); Nitrous Oxide (

N_2O

) matches with the dominant current anthropogenic ozone-depleting emission; Hydrochlorofluorocarbons (HCFCs) match with the transitional ozone-depleting substitutes containing hydrogen; and Methane (

CH_4

) matches with the short-lived climate pollutant primarily removed via hydroxyl radical (

\text{OH}^\bullet

) oxidation.

Each atmospheric gas is correctly paired with its specific radiative, chemical, or policy characteristic. Sulfur Hexafluoride holds the highest 100-year GWP among regulated greenhouse gases. Nitrous Oxide is the largest remaining unregulated anthropogenic contributor to stratospheric ozone depletion. HCFCs serve as hydrogen-containing transitional ODSs under phase-out. Methane is a short-lived climate pollutant mainly removed via tropospheric hydroxyl radical (

\text{OH}^\bullet

) oxidation.

Step-by-Step Solution

Identify the primary radiative property of Sulfur Hexafluoride (

SF_6

SF_6

is recognized by the IPCC as having an exceptionally high Global Warming Potential (

GWP_{100} \approx 23,500

) due to its long atmospheric lifetime (~3,200 years) and intense infrared absorption cross-section.

This establishes the match for Sulfur Hexafluoride.

Analyze the atmospheric chemistry impact of Nitrous Oxide (

N_2O

Agricultural and industrial emissions of

N_2O

photolyze in the stratosphere to yield

NO

radicals that catalyze ozone destruction. Because it is not regulated by the Montreal Protocol, it is currently the leading anthropogenic ozone-depleting substance emitted.

This links Nitrous Oxide to its status as the top remaining anthropogenic ODS emitter.

Examine the regulatory role of HCFCs in ozone protection policy.

HCFCs were introduced as first-generation temporary replacements for CFCs. Their C-H bonds allow partial degradation in the troposphere, reducing their Ozone Depletion Potential compared to CFCs, though they remain subject to global phase-out.

This confirms HCFCs as transitional compounds under the Montreal Protocol.

Determine the main removal sink for atmospheric Methane (

CH_4

Methane has an atmospheric lifetime of about 11.8 years. Its dominant atmospheric sink is oxidation by the hydroxyl radical (

\text{OH}^\bullet

) in the troposphere, forming water vapor and carbon dioxide.

This pairs Methane with oxidation by hydroxyl radicals.

Key Concept

Atmospheric behavior, radiative forcing capabilities, and regulatory classification of greenhouse gases and ozone-depleting substances.

Question 57Question →

With reference to statutory environmental institutions and bodies in India, consider the following statements:

1. The Central Pollution Control Board (CPCB) is a statutory body constituted under the Environment (Protection) Act, 1986.
2. The National Green Tribunal (NGT) is not bound by the procedure laid down under the Code of Civil Procedure, 1908, but is guided by principles of natural justice.
3. The Animal Welfare Board of India (AWBI) is a statutory advisory body established under the provisions of the Prevention of Cruelty to Animals Act, 1960.

Which of the statements given above are correct?

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

Show answer & explanation

Answer: 2 and 3 only

Answer

Statements 2 and 3 only are correct.

The correct option is the one identifying statements 2 and 3 only. Statement 2 is true because Section 19 of the NGT Act 2010 specifies that the tribunal is guided by natural justice principles rather than strict CPC procedures. Statement 3 is true as AWBI was created under Section 4 of the Prevention of Cruelty to Animals Act, 1960. Statement 1 is false because CPCB was established under the Water (Prevention and Control of Pollution) Act, 1974.

Step-by-Step Solution

Evaluate Statement 1 regarding the statutory origin of the Central Pollution Control Board (CPCB).

Statement 1 is incorrect. CPCB was constituted under Section 3 of the Water (Prevention and Control of Pollution) Act, 1974. It was later entrusted with powers under the Air (Prevention and Control of Pollution) Act, 1981, but was not founded under the Environment (Protection) Act, 1986.

Establishing the correct statutory parent act is essential for constitutional/statutory body classification in General Studies.

Evaluate Statement 2 regarding the procedural mandate of the National Green Tribunal (NGT).

Statement 2 is correct. As per Section 19 of the National Green Tribunal Act, 2010, the tribunal is explicitly exempted from being bound by the Code of Civil Procedure, 1908, and the Indian Evidence Act, 1872, and is guided by the principles of natural justice.

Understanding judicial vs quasi-judicial procedural flexibility of environmental tribunals.

Evaluate Statement 3 regarding the establishment of the Animal Welfare Board of India (AWBI).

Statement 3 is correct. The Animal Welfare Board of India is a statutory advisory body constituted under Section 4 of the Prevention of Cruelty to Animals Act, 1960, working under the Ministry of Environment, Forest and Climate Change.

Verifying statutory bodies dedicated to animal welfare and conservation governance in India.

Key Concept

Statutory foundation, parent legislation, and legal mandates of environmental bodies in India (CPCB, NGT, AWBI).

Question 58Question →

Arrange the following landmark Indian environmental acts and legislations in chronological order of their enactment, starting from the earliest to the most recent.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological order of enactment from earliest to most recent is: Water (Prevention and Control of Pollution) Act (1974), Air (Prevention and Control of Pollution) Act (1981), Environment (Protection) Act (1986), Biological Diversity Act (2002), and National Green Tribunal Act (2010).

The correct chronological sequence begins with the Water (Prevention and Control of Pollution) Act enacted in 1974, followed by the Air (Prevention and Control of Pollution) Act in 1981. Next is the umbrella Environment (Protection) Act passed in 1986 (prompted by the 1984 Bhopal Gas Leak). This is followed by the Biological Diversity Act enacted in 2002 pursuant to the 1992 CBD, and finally the National Green Tribunal Act enacted in 2010.

Step-by-Step Solution

Determine the exact enactment year for each of the specified legislative acts.

Water Act: 1974, Air Act: 1981, Environment (Protection) Act: 1986, Biological Diversity Act: 2002, National Green Tribunal Act: 2010.

Identifying enactment years is required to evaluate the chronological timeline.

Order the enactments chronologically from the earliest year to the latest year.

1974 (Water Act) → 1981 (Air Act) → 1986 (Environment Protection Act) → 2002 (Biological Diversity Act) → 2010 (NGT Act).

Sorting ascending by year establishes the correct temporal sequence.

Match the sorted timeline items back to their corresponding item identifiers.

item_2 → item_1 → item_4 → item_5 → item_3.

Maps the chronological sequence to the question's item IDs.

Key Concept

Chronological evolution of major environmental statutes in India

Question 59Question →

Following the successful phase-out of manufactured Chlorofluorocarbons (CFCs) under international environmental agreements, recent atmospheric assessments indicate that a specific compound has emerged as the single largest anthropogenic emission contributing to stratospheric ozone depletion, while also acting as a long-lived greenhouse gas with a 100-year Global Warming Potential nearly 273 times that of carbon dioxide ( $CO_2$ ). Which chemical compound is responsible for this dual atmospheric impact?

Nitrous oxide (

N_2O

)

Sulfur hexafluoride (

SF_6

)

Methane (

CH_4

)

Carbon tetrachloride (

CCl_4

)

Show answer & explanation

Answer: Nitrous oxide ( $N_2O$ )

Answer

Nitrous oxide (

N_2O

) is the correct choice because it is currently the most significant anthropogenic ozone-depleting substance emitted globally while also being a major greenhouse gas with a Global Warming Potential nearly 273 times that of

CO_2

Nitrous oxide (

N_2O

) is released primarily from agricultural soil management, synthetic fertilizers, and industrial processes. In the stratosphere, photolysis converts

N_2O

into reactive nitric oxide (

NO

) radicals, which catalytically destroy ozone. Because

N_2O

emissions are not restricted under the original Montreal Protocol in the same way as chlorofluorocarbons, it has become the single largest human-emitted ozone-depleting substance while maintaining a high Global Warming Potential (~273).

Step-by-Step Solution

Identify the chemical compound acting as both a major greenhouse gas and the leading current anthropogenic driver of stratospheric ozone depletion.

Evaluate compounds regulated under environmental frameworks for dual atmospheric roles.

With CFC emissions drastically reduced under the Montreal Protocol, agricultural and industrial emissions of Nitrous Oxide (

N_2O

) have become the largest un-phased anthropogenic ozone-depleting emission.

Verify atmospheric chemistry mechanisms and radiative forcing properties.

Confirm that

N_2O

breaks down into nitrogen oxides (

NO_x

) in the stratosphere, catalytically destroying ozone, and has a 100-year GWP around 273.

This matches both criteria stated in the stem.

Key Concept

Nitrous Oxide dual role in Climate Change and Stratospheric Ozone Depletion

Question 60Question →

Which of the following geographical regions of India are officially included within globally recognized biodiversity hotspots? (Select all correct options)

Select all that apply

Western Ghats

Nicobar Islands

Gangetic Plain

Thar Desert

Show answer & explanation

Answer: Western Ghats; Nicobar Islands

Answer

The Western Ghats and the Nicobar Islands are both officially included within global biodiversity hotspots in India.

The Western Ghats and the Nicobar Islands are correct because India is home to four global biodiversity hotspots: Western Ghats, Himalayas, Indo-Burma, and Sundaland (which encompasses the Nicobar Islands). Both regions possess extreme levels of species endemism coupled with severe habitat destruction.

Step-by-Step Solution

Identify the four global biodiversity hotspots associated with India.

The four regions are the Western Ghats (and Sri Lanka), the Eastern Himalayas (Himalaya hotspot), Indo-Burma, and Sundaland (which includes the Nicobar Islands).

Official conservation biology classification recognizes these specific zones based on species endemism and habitat threat levels.

Evaluate each choice against the recognized Indian biodiversity hotspots.

The Western Ghats forms its own hotspot region, and the Nicobar Islands fall under the Sundaland hotspot. The Gangetic Plain and Thar Desert are not designated hotspots.

Hotspots require at least 1,500 endemic vascular plant species and at least 70% loss of primary vegetation, criteria not met by major agricultural plains or arid desert belts.

Key Concept

Geographical distribution of global biodiversity hotspots in India

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