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.
Chapter Breakdown: Scroll →
The term ‘Intended Nationally Determined Contribution’ is sometimes seen in the news in the context of:
Detailed Explanation:
Answer: Option 2 — Plan of action outlined by the countries of the world to combat climate change.
Intended Nationally Determined Contributions (INDCs) are voluntary climate action plans submitted by countries before the Paris Agreement (2015). Each nation outlined its intended contributions to reduce greenhouse gas emissions, transition to renewable energy, and adapt to climate impacts based on its national circumstances and capabilities. Once countries ratified the Paris Agreement, these INDCs became Nationally Determined Contributions (NDCs) — the cornerstone of the global climate framework. They follow a bottom-up approach where countries independently determine their targets rather than having them imposed internationally.
In which of the following regions of India are you most likely to come across the ‘Great Indian Hornbill’ in its natural habitat?
Detailed Explanation:
Answer: Option 4 — Western Ghats
The Great Indian Hornbill (Buceros bicornis) is a large frugivorous bird native to the dense evergreen and moist deciduous forests of India. Its natural habitat in India is primarily concentrated in the Western Ghats, where it thrives in the tropical rainforests with abundant fruit-bearing trees. The bird is also found in the foothills of the Himalayas in the northeastern states, but among the given options, the Western Ghats is the correct answer. The species requires tall trees for nesting and roosting, making the sand deserts of northwest India, higher cold Himalayas of Jammu and Kashmir, and salt marshes of Gujarat unsuitable habitats. It is listed as vulnerable due to habitat loss and hunting pressure.
Which of the following are the key features of ‘National Ganga River Basin Authority (NGRBA)’?
- The river basin is the unit of planning and management.
- It spearheads the river conservation efforts at the national level.
- One of the Chief Ministers of the State through which the Ganga flows becomes the Chairman of NGRBA on a rotation basis.
Select the correct answer using the code given below.
Detailed Explanation:
Answer: Option 1 — 1 and 2 only
✅ Statement 1 – Correct: NGRBA adopts the river basin as the unit of planning and management, moving away from fragmented state-wise approaches to a holistic basin-level conservation strategy.
✅ Statement 2 – Correct: NGRBA was established to spearhead river conservation efforts at the national level for the Ganga. It functions as the apex planning, financing, monitoring, and coordinating authority for Ganga rejuvenation.
❌ Statement 3 – Incorrect: The Prime Minister of India serves as the Chairman of NGRBA, not Chief Ministers on rotation. Chief Ministers of Ganga basin states are members of the Authority along with relevant Union Cabinet Ministers.
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Which of the following best describes the aim of ‘Green India Mission’ of the Government of India?
- Incorporating environment benefits and costs into the Union and State Budgets thereby implementing the ‘green accounting’.
- Launching the second green revolution to enhance agriculture output so as to ensure food security to one and all in the future.
- Restoring and enhancing forest cover and responding to climate change by a combination of adaptation and mitigation measures.
Select the correct answer using the code given below
Detailed Explanation:
Answer: Option 3 — 3 only
❌ Statement 1 – Incorrect: Green accounting refers to incorporating environmental costs and benefits into national budgets, which is a separate economic initiative. The Green India Mission does not aim at implementing green accounting in Union and State budgets.
❌ Statement 2 – Incorrect: The Second Green Revolution focuses on enhancing agricultural productivity and food security. The Green India Mission, part of the National Action Plan on Climate Change (NAPCC), specifically targets forestry and forest cover, not agricultural output.
✅ Statement 3 – Correct: The National Mission for a Green India (GIM) aims to protect, restore, and enhance India's forest cover while responding to climate change through adaptation and mitigation measures. It targets increasing forest cover on 5 million hectares and improving quality on another 5 million hectares, thereby enhancing ecosystem services including carbon sequestration and biodiversity conservation.
What is ‘Greenhouse Gas Protocol’?
Detailed Explanation:
Answer: Option 1 — It is an international accounting tool for government and business leaders to understand, quantify and manage greenhouse gas emissions
The Greenhouse Gas Protocol is the most widely used global framework for measuring and managing greenhouse gas emissions. Developed by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), it provides standardized methods for organizations and governments to account for their carbon footprint. It is not a UN financial initiative, not a legally binding intergovernmental agreement, and not related to REDD+ initiatives hosted by the World Bank.
Which of the following is/are the advantage/advantages of practising drip irrigation?
- Reduction in weed
- Reduction in soil salinity
- Reduction in soil erosion
Select the correct answer using the code given below.
Detailed Explanation:
Answer: Option 3 — 1 and 3 only
✅ Statement 1 – Correct: Drip irrigation delivers water directly to the root zone of plants, keeping the soil surface relatively dry. Since weeds require moist topsoil to germinate and grow, restricting surface water availability significantly reduces weed proliferation compared to flood or sprinkler irrigation methods.
❌ Statement 2 – Incorrect: Drip irrigation does not directly reduce soil salinity. In fact, because water is applied in small quantities at specific points, salts can accumulate at the edges of the wetted zone. While proper management practices (like periodic leaching) can help control salinity, drip irrigation itself is not a method for reducing existing soil salinity.
✅ Statement 3 – Correct: By releasing water slowly and directly at the root zone, drip irrigation minimizes surface runoff and water flow across the soil surface. This controlled water application prevents the washing away of topsoil, thereby reducing soil erosion and preserving soil structure and fertility.
With reference to ‘Agenda 21’, sometimes seen in the news, consider the following statements:
- It is a global action plan for sustainable development.
- It originated in the World Summit on Sustainable Development held in Johannesburg in 2002
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 1 — 1 only
✅ Statement 1 – Correct: Agenda 21 is a comprehensive global action plan for sustainable development adopted at the United Nations Conference on Environment and Development (Earth Summit) in Rio de Janeiro in 1992. It addresses environmental, social, and economic dimensions of sustainable development across 40 chapters covering issues like poverty, consumption patterns, atmospheric protection, deforestation, desertification, oceans, biodiversity, and waste management.
❌ Statement 2 – Incorrect: Agenda 21 originated at the Rio Earth Summit in 1992, not at the World Summit on Sustainable Development held in Johannesburg in 2002. The Johannesburg Summit (Rio+10) reviewed progress on Agenda 21 implementation and produced the Johannesburg Plan of Implementation, which reaffirmed and built upon the original commitments.
Consider the following statements:
- The Sustainable Development Goals were first proposed in 1972 by a global think tank called the ‘Club of Rome’.
- The Sustainable Development Goals have to be achieved by 2030.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 2 — 2 only
❌ Statement 1 – Incorrect: The Sustainable Development Goals (SDGs) were not proposed by the Club of Rome in 1972. The Club of Rome published 'The Limits to Growth' report in 1972, which discussed environmental sustainability concerns. The concept of SDGs was proposed by Colombia at a preparatory event for the Rio+20 Conference held in Indonesia in July 2011. The SDGs were formally adopted by the UN General Assembly in September 2015 as part of the 2030 Agenda for Sustainable Development.
✅ Statement 2 – Correct: The Sustainable Development Goals are a set of 17 global goals adopted by all United Nations Member States in 2015. These goals address global challenges including poverty, inequality, climate change, environmental degradation, peace, and justice. The target year for achieving these goals is 2030, which is why they are also referred to as the 2030 Agenda.
Proper design and effective implementation of UN-REDD+ Programme can significantly contribute to -
- Protection of biodiversity
- Resilience of forest ecosystems
- Poverty reduction
Select the correct answer using the code given below
Detailed Explanation:
Answer: Option 4 — 1, 2 and 3
The UN-REDD+ (Reducing Emissions from Deforestation and Forest Degradation) Programme creates financial incentives for developing countries to reduce forest-based emissions while promoting sustainable forest management. All three statements are correct:
✅ Statement 1 – Correct: REDD+ protects biodiversity by preventing deforestation and forest degradation, thereby conserving the diverse species of flora and fauna that depend on forest ecosystems.
✅ Statement 2 – Correct: The programme enhances resilience of forest ecosystems by promoting sustainable forest management practices that help forests better withstand climate change impacts, natural disturbances, and environmental stresses.
✅ Statement 3 – Correct: REDD+ contributes to poverty reduction by providing financial incentives and alternative livelihood opportunities to forest-dependent communities, encouraging them to participate in sustainable forest conservation rather than exploitative practices.
‘Net metering’ is sometimes seen in the news in the context of promoting the -
Detailed Explanation:
Answer: Option 1 — production and use of solar energy by the households/consumers
Net metering is a billing mechanism that allows households and businesses with solar panel installations to send excess electricity generated during the day back to the power grid. In return, they receive credits on their electricity bills which can be used when they draw power from the grid during night-time or cloudy periods when solar production is low. This system promotes decentralized solar energy generation by making rooftop solar installations economically viable for individual consumers, as they effectively use the grid as a virtual battery without needing expensive physical storage systems.
With reference to ‘Red Sanders’, sometimes seen in the news, consider the following statements:
- It is a tree species found in a part of South India.
- It is one of the most important trees in the tropical rainforest areas of South India.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 1 — 1 only
✅ Statement 1 – Correct: Red Sanders (Pterocarpus santalinus), also known as Red Sandalwood, is a tree species endemic to the southern Eastern Ghats mountain range of South India, primarily found in the states of Andhra Pradesh and Tamil Nadu.
❌ Statement 2 – Incorrect: Red Sanders is not found in tropical rainforest areas. It grows in dry deciduous forests and semi-arid regions of the Eastern Ghats, thriving in scrub forests with rocky terrain and low rainfall conditions, which are distinctly different from tropical rainforest ecosystems.
Consider the following pairs:
| Terms sometimes seen in the news | Their origin |
|---|---|
| 1. Annex-I Countries | Cartagena Protocol |
| 2. Certified Emissions Reductions | Nagoya Protocol |
| 3. Clean Development Mechanism | Kyoto Protocol |
Which of the pairs given above is/are correctly matched?
Detailed Explanation:
Answer: Option 3 — 3 only
❌ Pair 1 – Incorrect: Annex-I Countries are listed under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol, not the Cartagena Protocol. The Cartagena Protocol deals with biosafety and the safe handling of living modified organisms.
❌ Pair 2 – Incorrect: Certified Emissions Reductions (CERs) are carbon credits issued under the Clean Development Mechanism of the Kyoto Protocol, not the Nagoya Protocol. The Nagoya Protocol concerns access to genetic resources and benefit-sharing.
✅ Pair 3 – Correct: Clean Development Mechanism (CDM) is indeed a mechanism established under the Kyoto Protocol. It allows developed countries to invest in emission reduction projects in developing countries and earn CERs as offsets against their emission reduction commitments.
Recently, our scientists have discovered a new and distinct species of banana plant which attains a height of about 11 metres and has orange-coloured fruit pulp. In which part of India has it been discovered?
Detailed Explanation:
The Musa indandamanensis, a new banana species reaching 11 meters in height with distinctive orange fruit pulp, was discovered by the Botanical Survey of India (BSI) in the tropical rainforests of Little Andaman Island.
This species is unique for its green flowers, large fruit bunch axis (three times normal size), cylindrical flowers (instead of conical), and orange pulp—making the Andaman Islands the correct answer.
With reference to an organization known as ‘Birdlife International’ which of the following statements is/are correct?
- It is a Global Partnership of Conservation Organizations.
- The concept of ‘biodiversity hotspots’ originated from this organization.
- It identifies the sites known/referred to as ‘Important Bird and Biodiversity Areas’.
Select the correct answer using the code given below.
Detailed Explanation:
✅ Statement 1 – Correct: BirdLife International is a global partnership of over 100 conservation NGOs working to conserve birds, their habitats, and biodiversity.
❌ Statement 2 – Incorrect: The biodiversity hotspots concept was originated by British ecologist Norman Myers (1988), later promoted by Conservation International, not BirdLife International.
✅ Statement 3 – Correct: BirdLife International identifies and monitors Important Bird and Biodiversity Areas (IBAs), a global network of critical sites for bird conservation and broader biodiversity.
Which one of the following is the best description of the term “ecosystem”?
Detailed Explanation:
Ecosystem = Biotic community (living organisms) + Abiotic environment (non-living factors like soil, water, air, sunlight) functioning together.
❌ Option 1: Describes only a biological community (lacks abiotic factors).
❌ Option 2: Defines the biosphere (entire zone of life on Earth).
✅ Option 3: Correctly captures both organisms and their environment as an integrated functional unit.
❌ Option 4: Refers to biota/biodiversity of a region (only living components).