UPSC CSE Prelims
Environment & Ecology Previous Year Questions (PYQs)
Solved Previous Year Questions (PYQs) for Environment & Ecology in UPSC CSE Prelims in English & Hindi Medium.
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"Momentum for Change: Climate Neutral Now" is an initiative launched by
Detailed Explanation:
Answer: Option 3 — The UNFCCC Secretariat
The "Momentum for Change: Climate Neutral Now" initiative was launched by the United Nations Framework Convention on Climate Change (UNFCCC) Secretariat in 2015 to encourage individuals, businesses, and governments to take voluntary action towards climate neutrality. In 2016, Climate Neutral Now became a new pillar under the broader "Momentum for Change" initiative, which highlights and promotes successful climate action worldwide.
📝 Short Notes: Climate Neutral Now Initiative
- Launch: Launched by UNFCCC Secretariat in 2015 to promote voluntary climate action towards climate neutrality
- Three-Step Process: (1) Measure climate footprint (greenhouse gas emissions), (2) Reduce emissions through sustainable practices and efficiency improvements, (3) Offset unavoidable emissions using UN-certified emission reductions (CERs)
- Momentum for Change: Climate Neutral Now was integrated as a pillar under the broader "Momentum for Change" initiative in 2016
- Target Audience: Individuals, companies, and governments worldwide
- Alignment: Supports Paris Agreement goals by fostering accountability and proactive engagement in climate action
- Recognition: Part of UNFCCC's efforts to showcase and scale up innovative climate solutions globally
The term "sixth mass extinction/sixth extinction" is often mentioned in the news in the context of the discussion of
Detailed Explanation:
Answer: Option 4 — Mankind's over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.
The term "sixth mass extinction" refers to the ongoing biodiversity crisis driven primarily by anthropogenic (human-caused) factors. Unlike previous mass extinctions caused by natural phenomena, the current extinction event is characterized by unprecedented rates of species loss due to human activities including habitat destruction, overexploitation of species, pollution, introduction of invasive species, and climate change. Scientists estimate that species are currently going extinct at rates 100 to 1,000 times higher than the natural background rate, making this a human-driven ecological catastrophe comparable to the five previous mass extinctions in Earth's 4.5-billion-year history.
📝 Short Notes: Mass Extinctions
| Extinction Event | Time Period | Species Lost | Cause |
|---|---|---|---|
| Ordovician-Silurian | ~445 million years ago | ~85% | Climate change, glaciation |
| Late Devonian | ~375 million years ago | ~75% | Ocean anoxia, climate change |
| Permian-Triassic ("Great Dying") | ~252 million years ago | ~96% | Volcanic eruptions, climate change |
| Triassic-Jurassic | ~201 million years ago | ~80% | Volcanic activity, climate change |
| Cretaceous-Paleogene | ~66 million years ago | ~76% (including dinosaurs) | Asteroid impact, volcanic activity |
| Sixth Extinction (Holocene) | Ongoing (present) | Unknown (in progress) | Human activities |
- Current extinction rate: 100-1,000 times higher than natural background rate
- Primary drivers: Habitat loss (deforestation, urbanization), overexploitation (hunting, fishing), pollution, invasive species, climate change
- Most affected groups: Amphibians, marine mammals, large predators, island species
- IUCN Red List: Over 40,000 species currently threatened with extinction
- Holocene extinction: Another name for the sixth extinction, referring to the current geological epoch
With reference to the circumstances in Indian agriculture, the concept of "Conservation Agriculture" assumes significance. Which of the following fall under the Conservation Agriculture?
- Avoiding monoculture practices
- Adopting minimum tillage
- Avoiding the cultivation of plantation crops
- Using crop residues to cover the soil surface
- Adopting spatial and temporal crop sequencing/crop rotations
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 4 — 2, 4 and 5
Conservation Agriculture is based on three core principles: minimum soil disturbance (minimum/no tillage), permanent soil cover (using crop residues or mulches), and crop diversification (through rotations and intercropping). Options 2, 4, and 5 directly align with these principles, while options 1 and 3 are not recognized components of Conservation Agriculture.
✅ Statement 2 – Correct: Minimum tillage is a fundamental principle of Conservation Agriculture that reduces soil disturbance and erosion.
❌ Statement 1 – Incorrect: While crop diversification is encouraged, avoiding monoculture is not explicitly defined as a Conservation Agriculture practice.
❌ Statement 3 – Incorrect: Conservation Agriculture does not exclude plantation crops; these can be cultivated using conservation practices.
✅ Statement 4 – Correct: Maintaining permanent soil cover using crop residues is a core principle of Conservation Agriculture.
✅ Statement 5 – Correct: Crop rotations and sequencing are essential for crop diversification under Conservation Agriculture.
📝 Short Notes: Conservation Agriculture
- Definition: A sustainable farming system based on three interlinked principles that enhance agricultural productivity while protecting the environment.
- Three Core Principles:
- Minimum Soil Disturbance: No-till or minimum tillage farming reduces soil erosion and improves soil structure.
- Permanent Soil Cover: Use of crop residues, mulches, or cover crops to protect soil from erosion and maintain moisture.
- Crop Diversification: Crop rotations, intercropping, and crop sequencing to improve soil fertility and break pest cycles.
- Benefits: Reduces soil erosion, improves water retention, enhances soil organic matter, reduces input costs, and increases resilience to climate variability.
- FAO Support: The Food and Agriculture Organization (FAO) actively promotes Conservation Agriculture globally as a climate-smart practice.
- Application in India: Particularly relevant in water-stressed regions and areas with declining soil health; promoted through various government schemes.
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In which one of the following States is Pakhui Wildlife Sanctuary located?
Detailed Explanation:
Answer: Option 1 — Arunachal Pradesh
Pakhui Wildlife Sanctuary is located in the East Kameng district of Arunachal Pradesh. It is part of the Kameng Elephant Reserve and is contiguous with Pakke Tiger Reserve, known for its rich biodiversity including hornbills, elephants, and tigers. The sanctuary is traversed by the Bhareli (Pakke) and Bamadi rivers, supporting diverse flora and fauna.
📝 Short Notes: Major Wildlife Sanctuaries in Northeast India
| State | Important Wildlife Sanctuaries/National Parks | Key Species |
|---|---|---|
| Arunachal Pradesh | Pakhui (Pakke) WLS, Namdapha NP, Mouling NP, Kamlang WLS | Hornbills, Elephants, Tigers, Snow Leopards |
| Manipur | Keibul Lamjao NP, Yangoupokpi-Lokchao WLS | Sangai (Dancing Deer), Hoolock Gibbon |
| Meghalaya | Nokrek NP, Balpakram NP | Red Panda, Clouded Leopard, Asian Elephant |
| Nagaland | Intanki NP, Fakim WLS | Hoolock Gibbon, Blyth's Tragopan |
| Assam | Kaziranga NP, Manas NP, Dibru-Saikhowa NP | One-horned Rhino, Wild Water Buffalo, Gangetic Dolphin |
With reference to solar power production in India, consider the following statements:
- India is the third largest in the world in the manufacture of silicon wafers used in photovoltaic units.
- The solar power tariffs are determined by the Solar Energy Corporation of India.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 4 — Neither 1 nor 2
Both statements about solar power production in India are incorrect. India is not among the top three global manufacturers of silicon wafers for photovoltaic units, and SECI does not determine solar power tariffs but facilitates project implementation.
❌ Statement 1 – Incorrect: India does not rank among the top three manufacturers of silicon wafers for photovoltaic units; China, Taiwan, and South Korea dominate this sector with China alone accounting for over 90% of global production.
❌ Statement 2 – Incorrect: The Solar Energy Corporation of India (SECI) does not determine solar power tariffs; tariffs are determined through a competitive bidding process conducted by various implementing agencies, with SECI acting as a facilitator and intermediary.
📝 Short Notes: Solar Power in India
- Solar Energy Corporation of India (SECI): A government-owned enterprise under the Ministry of New and Renewable Energy (MNRE), established in 2011 to facilitate solar energy deployment through competitive bidding, tendering, and project implementation.
- Tariff Determination: Solar power tariffs in India are market-driven and determined through reverse auction mechanisms where developers bid competitively; the lowest bidder wins the contract, ensuring cost-effective power procurement.
- Silicon Wafer Manufacturing: India's domestic solar manufacturing capacity is limited, with heavy reliance on imports (especially from China) for solar cells, modules, and silicon wafers; the government is promoting domestic manufacturing through Production Linked Incentive (PLI) schemes.
- Global Leaders: China dominates global solar manufacturing with over 90% market share in silicon wafers, followed by Taiwan and South Korea; India is focusing on building manufacturing capacity through policies like Atmanirbhar Bharat.
- India's Solar Capacity: India ranks among the top 5 countries globally in installed solar capacity and aims to achieve 500 GW of renewable energy capacity by 2030 as part of its climate commitments.
In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration?
- Abandoned and uneconomic coal seams
- Depleted oil and gas reservoirs
- Subterranean deep saline formations
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 4 — 1, 2 and 3
All three options represent viable geological sites for carbon sequestration, which is the process of capturing and storing atmospheric carbon dioxide to mitigate global warming. These geological formations possess the necessary characteristics—porosity, permeability, and secure cap rocks—to safely store CO₂ underground for extended periods.
✅ Statement 1 – Correct: Abandoned and uneconomic coal seams can store CO₂ through a process called coal seam carbon sequestration, where CO₂ is adsorbed onto the coal matrix, potentially displacing methane in the process.
✅ Statement 2 – Correct: Depleted oil and gas reservoirs are proven storage sites as they have already trapped hydrocarbons for millions of years, indicating their capacity to securely contain injected CO₂ with existing infrastructure.
✅ Statement 3 – Correct: Subterranean deep saline formations (aquifers) are among the most promising and abundant carbon storage sites globally, offering vast storage capacity far below freshwater resources with minimal environmental risk.
Consider the following statements in respect of Trade-Related Analysis of Fauna and Flora in Commerce (TRAFFIC):
- TRAFFIC is a bureau under the United Nations Environment Programme (UNEP).
- The mission of TRAFFIC is to ensure that trade in wild plants and animals is not a threat to the conservation of nature.
Which of the above statements is/are correct?
Detailed Explanation:
Answer: Option 2 — 2 only
TRAFFIC is a joint initiative of WWF (World Wide Fund for Nature) and IUCN (International Union for Conservation of Nature), not a bureau under UNEP. Its mission is to ensure that trade in wild plants and animals does not threaten the conservation of nature.
❌ Statement 1 – Incorrect: TRAFFIC is not a bureau under UNEP; it is a joint programme of WWF and IUCN established in 1976.
✅ Statement 2 – Correct: TRAFFIC's mission is indeed to ensure that trade in wild plants and animals is not a threat to the conservation of nature and works to promote sustainable and legal wildlife trade.
With reference to ‘Global Climate Change Alliance’, which of the following statements is/are correct?
- It is an initiative of the European Union.
- It provides technical and financial support to targeted developing countries to integrate climate change into their development policies and budgets.
- It is coordinated by the World Resources Institute (WRI) and World Business Council for Sustainable Development (WBCSD).
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 1 — 1 and 2 only
The Global Climate Change Alliance (GCCA) is a flagship initiative of the European Union launched in 2007 to support developing countries, particularly LDCs and SIDS, in addressing climate change challenges. It provides both technical and financial assistance to help integrate climate adaptation and mitigation strategies into national development policies and budgets.
✅ Statement 1 – Correct: The GCCA is indeed an initiative of the European Union, established to strengthen dialogue and cooperation with developing countries on climate change.
✅ Statement 2 – Correct: A primary objective of the GCCA is to provide technical and financial support to targeted developing countries to integrate climate change into their development policies and budgets.
❌ Statement 3 – Incorrect: The GCCA is coordinated by the European Commission, not by the World Resources Institute (WRI) or the World Business Council for Sustainable Development (WBCSD).
Due to some reasons if there is a huge fall in the population of species of butterflies, what could be its likely consequence/consequences?
- Pollination of some plants could be adversely affected.
- There could be a drastic increase in the fungal infections of some cultivated plants.
- It could lead to a fall in the population of some species of wasps, spiders and birds.
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 3 — 1 and 3 only
Butterflies play a crucial role as pollinators and as prey in food webs. A significant decline in butterfly populations would adversely affect pollination of many flowering plants and reduce food availability for their predators like wasps, spiders, and insectivorous birds, leading to cascading ecological effects.
✅ Statement 1 – Correct: Butterflies are important pollinators for numerous flowering plants, and their population decline would negatively impact pollination success, affecting fruit and seed production.
❌ Statement 2 – Incorrect: Butterfly population decline is not directly linked to increased fungal infections in cultivated plants; fungal diseases are primarily influenced by environmental factors like humidity, temperature, and plant health rather than butterfly populations.
✅ Statement 3 – Correct: Butterflies serve as a critical food source for various predators including wasps, spiders, and insectivorous birds; their decline would disrupt the food chain and negatively impact these predator populations.
Biological Oxygen Demand (BOD) is a standard criterion for -
Detailed Explanation:
Answer: Option 3 — Pollution assay in aquatic ecosystems
Biological Oxygen Demand (BOD) is a standard criterion for measuring the amount of dissolved oxygen consumed by microorganisms while decomposing organic matter in water bodies. It serves as a key indicator of water pollution—higher BOD values indicate greater organic pollution and potential harm to aquatic life due to oxygen depletion. BOD testing is widely used in environmental monitoring to assess the health and quality of aquatic ecosystems.
Consider the following statements:
- Climate and Clean Air Coalition (CCAC) to Reduce Short-Lived Climate Pollutants is a unique initiative of G20 group of countries.
- The CCAC focuses on methane, black carbon and hydrofluorocarbons.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 2 — 2 only
The Climate and Clean Air Coalition (CCAC) was launched in 2012 by UNEP and six founding countries (Bangladesh, Canada, Ghana, Mexico, Sweden, and the United States), not exclusively by the G20. It has since expanded to include over 160 partners worldwide. The CCAC specifically targets Short-Lived Climate Pollutants (SLCPs) that have significant warming potential but remain in the atmosphere for shorter periods than CO₂.
❌ Statement 1 – Incorrect: CCAC is not a unique initiative of the G20; it was launched by UNEP and six countries and has grown into a global coalition with diverse membership beyond G20.
✅ Statement 2 – Correct: The CCAC's primary focus is on reducing methane (CH₄), black carbon (BC), and hydrofluorocarbons (HFCs), which are potent short-lived climate pollutants.
From the ecological point of view, which one of the following assumes importance in being a good link between the Eastern Ghats and the Western Ghats?
Detailed Explanation:
Answer: Option 1 — Sathyamangalam Tiger Reserve
Sathyamangalam Tiger Reserve (STR) in Tamil Nadu is the largest tiger reserve in the state and serves as a crucial wildlife corridor within the Nilgiri Biosphere Reserve. It acts as a vital ecological link connecting the Western Ghats with the Eastern Ghats, facilitating genetic flow and wildlife movement between these two mountain ranges. STR is contiguous with several protected areas including Biligiriranga Swamy Temple Wildlife Sanctuary, Sigur Plateau, Mudumalai National Park, and Bandipur National Park, making it ecologically significant for biodiversity conservation and maintaining landscape connectivity between the Eastern and Western Ghats.
According to the Wildlife (Protection) Act, 1972, which of the following animals cannot be hunted by any person except under some provisions provided by law?
- Gharial
- Indian wild ass
- Wild Buffalo
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 4 — 1, 2 and 3
All three animals—Gharial, Indian wild ass, and Wild Buffalo—are listed in Schedule I of the Wildlife (Protection) Act, 1972, which provides the highest level of protection. Schedule I species cannot be hunted by any person except under exceptional provisions such as disease control or to prevent human attacks, making hunting of all three animals illegal under normal circumstances.
✅ Statement 1 – Correct: Gharial is listed in Schedule I and enjoys absolute protection from hunting.
✅ Statement 2 – Correct: Indian wild ass is listed in Schedule I and is protected from hunting.
✅ Statement 3 – Correct: Wild Buffalo is listed in Schedule I and cannot be hunted except under specific legal provisions.
In the context of solving pollution problems, what is/are the advantage/advantages of bioremediation technique?
- It is a technique for cleaning up pollution by enhancing the same biodegradation process that occurs in nature.
- Any contaminant with heavy metals such as cadmium and lead can be readily and completely treated by bioremediation using microorganisms.
- Genetic engineering can be used to create microorganisms specifically designed for bioremediation.
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 3 — 1 and 3 only
Bioremediation is a pollution control technique that uses living organisms, primarily microorganisms, to degrade or neutralize environmental contaminants by enhancing natural biodegradation processes. While genetic engineering can create specialized microorganisms for targeted bioremediation, heavy metals like cadmium and lead cannot be readily or completely treated through this technique as they are elements that cannot be biodegraded.
✅ Statement 1 – Correct: Bioremediation works by enhancing the natural biodegradation processes that occur in nature, using microorganisms to break down pollutants in soil, water, or other environments.
❌ Statement 2 – Incorrect: Heavy metals like cadmium and lead cannot be readily and completely treated by bioremediation because they are elemental pollutants that cannot be biodegraded, though they may be transformed or immobilized.
✅ Statement 3 – Correct: Genetic engineering techniques can be used to design microorganisms with enhanced or specific capabilities to target particular contaminants for more effective bioremediation.
Recently there was a proposal to translocate some of the lions from their natural habitat in Gujarat to which one of the following sites?
Detailed Explanation:
Answer: Option 4 — Kuno Palpur Wildlife Sanctuary
The Ministry of Environment approved Kuno Palpur Wildlife Sanctuary (now Kuno National Park) in Madhya Pradesh as the second home for translocating Asiatic lions from Gir National Park in Gujarat. This translocation was proposed to create a second viable population of Asiatic lions to ensure their long-term survival and reduce the risk of extinction from disease outbreaks or natural disasters at a single location. However, the translocation has faced delays due to various administrative and conservation concerns.