Environment and Ecology has emerged as one of the most high-scoring and decisive sections in the UPSC CSE Prelims. Over the past decade, 15–20 questions are asked every year, many of them concept-based yet current-oriented. The high repetition of themes makes this subject unique.
The UPSC Environment syllabus overlaps with Current Affairs, Geography, Science etc. Aspirants who master the repeated core areas often secure a significant edge.
Key reasons:
Environment and Ecology remain a high-weightage and strategically important section in UPSC Prelims, with questions that are both factual and conceptual. Most questions are linked to current environmental issues, which are often integrated with government schemes, biodiversity, climate change, conservation efforts and international environmental agreements. Every year, UPSC maintains a healthy balance between static concepts and dynamic current affairs, making Environment and Ecology PYQs highly predictable in terms of themes. The year-wise trend of Environment and Ecology questions in UPSC Prelims clearly reflects its consistent importance:
|
Year |
Number of Environment & Ecology Questions |
|
2025 |
13 |
|
2024 |
14 |
|
2023 |
14 |
|
2022 |
12 |
|
2021 |
20 |
|
2020 |
22 |
|
2019 |
21 |
|
2018 |
17 |
|
2017 |
15 |
This trend clearly shows that Environment and Ecology is one of the most reliable scoring areas in UPSC Prelims, where a strong grasp of static fundamentals combined with current affairs can significantly improve an aspirant’s score.
1) Ecology Basics – The Backbone of Environment Questions
This theme forms the conceptual foundation of Environment and Ecology questions in UPSC Prelims and appears almost every year. It covers the fundamentals of ecology, including ecosystem structure and function, food chain vs food web, energy flow, ecological pyramids (number, biomass and energy), biogeochemical cycles such as carbon, nitrogen and phosphorus, ecological succession, ecological niche and habitat. Questions from this area test conceptual clarity rather than rote memorisation.
Some Previous Years Questions from this Theme:
1] With reference to the planet Earth, consider the following statements: [2025/A-40]
I. Rain forests produce more oxygen than that produced by oceans.
II. Marine phytoplankton and photosynthetic bacteria produce about 50% of world’s oxygen.
III. Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric air.
Which of the statements given above is/are correct?
a) I and II
b) II only
c) I and III
d) None of the above statements is correct
Q] Which one of the following shows a unique relationship with an insect that has co-evolved with it and that is the only insect that can pollinate this tree? [2024]
a) Fig
b) Mahua
c) Sandalwood
d) Silk cotton
Q] Which of the following organisms perform waggle dance for others of their kin to indicate the direction and the distance to a source of their food? [2023]
a) Butterflies b) Dragonflies
c) Honeybees d) Wasps
2) India’s Biodiversity and Conservation
This is the most asked and most scoring theme in Environment for UPSC Prelims. UPSC frequently frames questions on types of biodiversity (genetic, species and ecosystem), biodiversity hotspots...especially Western Ghats and Himalayas, endemism, keystone species, flagship species, umbrella species and indicator species, along with their ecological roles. This theme has a strong overlap with current affairs, particularly when species or regions are in news, making it one of the most repeated Environment topics.
Some Previous Years Questions from this Theme:
How many of the above pairs are correctly matched?
a) Only two
b) Only three
c) Only four
d) All the five
Consider the following: [2024]
1. Cashew
2. Papaya
3. Red sanders
How many of the above trees are actually native to India?
a) Only one
b) Only two
c) All three
d) None
Consider the following trees: [2023]
1. Jackfruit (Artocarpus heterophyllus)
2. Mahua (Madhuca indica)
3. Teak (Tectona grandis)
How many of the above are deciduous trees?
a) Only one
b) Only two
c) All three
d) None
With reference to “Gucchi” sometimes mentioned in the news, consider the following statements: [2022]
1. It is a fungus.
2. It grows in some Himalayan forest areas.
3. It is commercially cultivated in the Himalayan foothills of north-eastern India.
Which of the statements given above is/are correct?
a) 1 only
b) 3 only
c) 1 and 2
d) 2 and 3
3) Species in News
Almost every Prelims paper includes questions on species in news, making it a high-certainty question area. The focus is usually on habitat and distribution, IUCN Red List category, conservation status in India and unique ecological traits. Frequently repeated species include Tiger, Snow Leopard, Gharial, Gangetic Dolphin, Olive Ridley Turtle, Great Indian Bustard and Asian Elephant. Questions are often framed by linking species with their ecosystem, habitat or conservation programme.
Consider the following Fauna: [2023]
1. Lion-tailed Macaque
2. Malabar Civet
3. Sambar Deer
How many of the above are generally nocturnal or most active after sunset?
a) Only one
b) Only two
c) All three
d) None
Which of the following is not a bird? [2022]
a) Golden Mahseer
b) Indian Nightjar
c) Spoonbill
d) White Ibisw
With reference to Indian elephants, consider the following statements: [2020]
1. The leader of an elephant group is a female.
2. The maximum gestation period can be 22 months.
3. An elephant can normally go on calving till the age of 40 years only.
4. Among the States in India, the highest elephant population is in Kerala.
Which of the statements given above is/are correct?
a) 1 and 2 only
b) 2 and 4 only
c) 3 only
d) 1, 3 and 4 only
Consider the following statements: [2019]
1. Asiatic lion is naturally found in India only.
2. Double-humped camel is naturally found in India only.
3. One-horned rhinoceros is naturally found in India only.
Which of the statements given above is/are correct?
a) 1 only
b) 2 only
c) 1 and 3 only
d) 1, 2 and 3
4) Protected Areas and Conservation Models in India
UPSC regularly asks statement-based and analytical questions from this theme. It includes National Parks vs Wildlife Sanctuaries, Biosphere Reserves (core, buffer and transition zones), Tiger Reserves under NTCA, Ramsar wetlands and Marine Protected Areas. Questions typically test understanding of legal status, governance structure and conservation objectives, making this a highly repeated area.
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 2 only
(c) 1 and 3
(d) 3 only
Consider the following statements:
Once the Central Government notifies an area as a ‘Community Reserve’
How many of the above statements are correct? [UPSC Civil Services Exam – 2023 Prelims]
(a) Only one
(b) Only two
(c) Only three
(d) All four
Which of the following are the most likely places to find the musk deer in its natural habitat? [2020]
1. Askot Wildlife Sanctuary
2. Gangotri National Park
3. Kishanpur Wildlife Sanctuary
4. Manas National Park
Select the correct answer using the code given below:
a) 1 and 2 only
b) 2 and 3 only
c) 3 and 4 only
d) 1 and 4 only
5) Global Climate Agreements and Environmental Conventions
This is a high-confidence scoring area in UPSC Prelims. UPSC regularly tests knowledge of UNFCCC, Kyoto Protocol, Paris Agreement, Nationally Determined Contributions (NDCs), IPCC reports, Global Stocktake, Convention on Biological Diversity (CBD), Ramsar Convention and CITES. Questions focus on objectives, principles and mechanisms, rather than dates or numerical targets.
Some Previous Years Questions from this Theme:
Which one of the following is correct in respect of the above statements?
a) Both Statement II and Statement III are correct and both of them explain Statement I
b) Both Statement II and Statement III are correct but only one of them explains Statement I
c) Only one of the Statements II and III is correct and that explains Statement I
d) Neither Statement II nor Statement III is correct
Consider the following statements: [2025/A-34]
Statement I: Article 6 of the Paris Agreement on climate change is frequently discussed in global discussions on sustainable development and climate change.
Statement II: Article 6 of the Paris Agreement on climate change sets out the principles of carbon markets.
Statement III: Article 6 of the Paris Agreement on climate change intends to promote inter-country non-market strategies to reach their climate targets.
Which one of the following is correct in respect of the above statements?
a) Both Statement II and Statement III are correct and both of them explain Statement I
b) Both Statement II and Statement III are correct but only one of them explains Statement I
c) Only one of the Statements II and III is correct and that explains Statement I
d) Neither Statement II nor Statement III is correct
‘Invasive Species Specialist Group’ (that develops Global Invasive Species Database) belongs to which one of the following organizations? [2023]
a) The International Union for Conservation of Nature
b) The United Nations Environment Programme
c) The United Nations World Commission for Environment and Development
d) The World Wide Fund for Nature
Consider the following statements: [2023]
Statement-I :
Carbon markets are likely to be one of the most widespread tools in the fight against climate change.
Statement-II :
Carbon market transfer resources from private sector to the State.
Which of the following is correct in respect of the above statements?
a) Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I.
b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I.
c) Statement-I is correct but Statement-II is incorrect.
d) Statement-I is incorrect but Statement-II is correct.
6) Environmental Pollution and Remedies
Pollution-related questions are logic-based rather than chemistry-heavy. This theme includes air pollution (PM2.5, PM10 and ozone), water pollution such as eutrophication, soil contamination, noise pollution, biomagnification vs bioaccumulation, waste management rules and pollution control mechanisms. UPSC often tests the impact of pollutants and remedial measures, making it a repeatedly asked theme.
Some Previous Years Questions from this Theme:
Q] Consider the following: [2025/A-44]
I. Cigarette butts
II. Eyeglass lenses
III. Car tyres How many of them contain plastic?
a) Only one
b) Only two
c) All the three
d) None
Artificial way of causing rainfall to reduce air pollution makes use of [2025/A-85]
a) silver iodide and potassium iodide
b) silver nitrate and potassium iodide
c) silver iodide and potassium nitrate
d) silver nitrate and potassium chloride
With reference to Perfluoroalkyl and polyfluoroalkyl substances (PFAS) that are used in making many consumer products, consider the following statements: [2024]
1. PFAS are found to be widespread in drinking water, food and food packaging materials.
2. PFAS are not easily degraded in the environment.
3. Persistent exposure to PFAS can lead to bioaccumulation in animal bodies.
Which of the statements given above are correct?
a) 1 and 2 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3
According to the Environmental Protection Agency (EPA), which one of the following is the largest source of Sulphur dioxide emissions? [2024]
a) Locomotives using fossil fuels
b) Ships using fossil fuels
c) Extraction of metals from ores
d) Power plants using fossil fuels
7) India’s Environmental Laws, Institutions and Conservation Efforts
Static environmental laws are asked repeatedly with conceptual twists. This theme covers the Environment Protection Act, 1986; Wildlife Protection Act, 1972; Forest Conservation Act; Biological Diversity Act, 2002; National Green Tribunal (NGT), along with government conservation schemes and institutions. Questions are usually statement-based and require clarity on powers, objectives and enforcement mechanisms.
Q] Consider the following statements: [2023]
Once the Central Government notifies an area as a ‘Community Reserve’
1. The Chief Wildlife Warden of the State becomes the governing authority of such forest
2. Hunting is not allowed in such area
3. People of such area are allowed to collect non-timber forest produce
4. People of such area are allowed traditional agricultural practices
How many of the above statements are correct?
a) Only one
b) Only two
c) Only three
d) All Four
Which one of the following has been constituted under the Environment (Protection) Act, 1986? [2022]
a) Central Water Commission
b) Central Ground Water Board
c) Central Ground Water Authority
d) National Water Development Agency
If a particular plant species is placed under Schedule VI of The Wildlife Protection Act, 1972, what is the implication? [2020]
a) A licence is required to cultivate that plant.
b) Such a plant cannot be cultivated under any circumstances.
c) It is a Genetically Modified crop plant.
d) Such a plant is invasive and harmful to the ecosystem.
This theme links environmental sustainability with agriculture. It includes sustainable agriculture, soil health, fertilizers and pesticides, organic farming, climate-resilient crops and agro-ecological practices. Questions often integrate agriculture with climate change, biodiversity loss and resource conservation, making it an emerging repeated area in UPSC Prelims.
Some Previous Years Questions from this Theme:
Which of the following are nitrogen-fixing plants? [2022]
1. Alfalfa
2. Amaranth
3. Chickpea
4. Clover
5. Purslane (Kulfa)
6. Spinach
Select the correct answer using the code given below:
a) 1, 3 and 4 only
b) 1, 3, 5 and 6 only
c) 2, 4, 5 and 6 only
d) 1, 2, 4, 5 and 6
“System of Rice Intensification” of cultivation, in which alternate wetting and drying of rice fields is practised, results in: [2022]
1. Reduced seed requirement
2. Reduced methane production
3. Reduced electricity consumptionSelect the correct answer using the code given below:
a) 1 and 2 only
b) 2 and 3 only
c) 1 and 3 only
d) 1, 2 and 3
In the context of India, which of the following is/are considered to be practice(s) of eco-friendly agriculture? [2020]
1. Crop diversification
2. Legume intensification
3. Tensiometer use
4. Vertical farmingSelect the correct answer using the code given below:
a) 1, 2 and 3 only
b) 3 only
c) 4 only
d) 1, 2, 3 and 4
What is the use of biochar in farming? [2020]
1. Biochar can be used as a part of the growing medium in vertical farming.
2. When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms.
3. When biochar is a part of the growing medium, it enables the growing medium to retain water for longer time.Which of the statements given above is/are correct?
a) 1 and 2 only
b) 2 only
c) 1 and 3 only
d) 1, 2 and 3
This area has gained importance due to India’s climate commitments and energy transition goals. UPSC asks questions on solar energy, wind energy, bioenergy, Green Hydrogen Mission, energy efficiency, circular economy and Sustainable Development Goals (SDGs). Questions are usually framed around sustainability and long-term environmental impact.
Some Previous Years Questions from this Theme:
Consider the following statements: [2025/A-63]
Statement I: Of the two major ethanol producers in the world, i.e., Brazil and the United States of America, the former produces more ethanol than the latter.
Statement II: Unlike in the United States of America where corn is the principal feedstock for ethanol production, sugarcane is the principal feedstock for ethanol production in Brazil.
Which of the statements given above are correct?
a) Both Statement I and Statement II are correct and Statement II explains Statement I
b) Both Statement I and Statement II are correct but Statement II does not explain Statement I
c) Statement I is correct but Statement II is not correct
d) Statement I is not correct but Statement II is correct
Consider the following: [2024]
1. Battery storage
2. Biomass generators
3. Fuel cells
4. Rooftop solar photovoltaic units
How many’ of the above are considered “Distributed Energy Resources”?
a) Only one
b) Only two
c) Only three
d) All four
Consider the following materials: [2024]
1. Agricultural residues
2. Corn grain
3. Wastewater treatment sludge
4. Wood mill waste
Which of the above can be used as feedstock for producing Sustainable Aviation Fuel?
a) 1 and 2 only
b) 3 and 4 only
c) 1, 2, 3 and 4
d)1, 3 and 4 only
One of the following is the exhaust pipe emission from Fuel Cell Electric Vehicles, powered by hydrogen? [2024]
a) Hydrogen peroxide
b) Hydronium
c) Oxygen
d) Water Vapour
Environment is not about memorisation. It is about recognising patterns. UPSC may change questions, but themes repeat. If you prepare these core areas thoroughly, Environment can become your strongest scoring section in UPSC CSE Prelims 2026.
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