UPSC Prelims 2012 Environment questions: topic-wise weightage
UPSC Prelims 2012 asked 19 environment questions in GS Paper I, spread over 5 topics. See the environment weightage for 2012 below, then attempt each question with the official answer and an explanation.
Environment 2012: questions by topic
- Ecology and ecosystems3
- Biodiversity and species6
- Protected areas and conservation3
- Climate change and international conventions4
- Pollution, environmental laws and green technology3
Counted from the 19 questions on this page, tagged by topic in the Battle IAS PYQ bank.
Seeing 19 Environment questions spread over 5 topics can feel overwhelming. That's exactly why the Battle IAS PYQ Book maps every question topic by topic, so you know what to study first. Download free sample
Ecology and ecosystems 3
Consider the following kinds of organisms :
- 1. Bat
- 2. Bee
- 3. Bird
Which of the above is/are pollinating agent/agents?
Answer (d) & explanation
All three are correct (d). Bees are the best-known pollinators of crops and wild plants. Birds, such as sunbirds in India and hummingbirds in the Americas, pollinate many red and tubular flowers (ornithophily). Bats, especially fruit and nectar bats, pollinate night-blooming plants such as banana, durian, mahua and agave (chiropterophily). So options (a), (b) and (c) leave out real pollinators.
Notice the stakes: about 75% of leading food crops benefit from animal pollination. Pollinator decline from neonicotinoid pesticides, habitat loss and climate change worries scientists; the EU restricted neonicotinoids in 2018. India's National Beekeeping and Honey Mission (2020) promotes the 'Sweet Revolution'. Trap: bats are often seen only as pests.
Answer as per the official UPSC answer key.
The Millennium Ecosystem Assessment describes the following major categories of ecosystem services—provisioning, supporting, regulating, preserving and cultural. Which one of the following is supporting service?
Answer (c) & explanation
Nutrient cycling and crop pollination is correct per UPSC's key (c), but pollination's place is doubtful. In the Millennium Ecosystem Assessment (2005), provisioning services give products such as food and water (a), regulating services control processes such as climate and disease (b), and supporting services keep everything running: nutrient cycling, soil formation and primary production. The MEA itself lists pollination under regulating services, so (c) is only half right; UPSC chose it as the best fit. (d) is wrong: 'maintenance of diversity' is a habitat idea, not an MEA supporting service as worded.
Notice the wider idea: the MEA has four categories, not five; 'preserving' in the question is not one of them. Cultural services include recreation and spiritual value. Trap: the stem adds a fake category.
Answer as per the official UPSC answer key.
What would happen if phytoplankton of an ocean is completely destroyed for some reason?
- 1. The ocean as a carbon sink would be adversely affected.
- 2. The food chains in the ocean would be adversely affected.
- 3. The density of ocean water would drastically decrease.
Select the correct answer using the codes given below :
Answer (a) & explanation
Statements 1 and 2 are correct (a). Phytoplankton are the ocean's microscopic plants. Through photosynthesis they absorb CO₂ and, when they die and sink, carry carbon to the deep sea: the biological pump, which makes the ocean a carbon sink (1). They form the base of marine food chains, feeding zooplankton, fish and whales (2). Statement 3 is wrong: seawater density depends on temperature and salinity, not on plankton. So (b), (c) and (d) fail.
Notice the scale: phytoplankton produce about half of the world's oxygen. Ocean warming and acidification threaten them, and blooms can turn harmful. Satellites track them through ocean colour, as India's Oceansat does to forecast fishing zones. Trap: losing plankton would not change water density.
Answer as per the official UPSC answer key.
Biodiversity and species 6
How does National Biodiversity Authority (NBA) help in protecting the Indian agriculture?
- 1. NBA checks the biopiracy and protects the indigenous and traditional genetic resources.
- 2. NBA directly monitors and supervises the scientific research on genetic modification of crop plants.
- 3. Application for Intellectual Property Rights related to genetic/biological resources cannot be made without the approval of NBA.
Which of the statements given above is/are correct?
Answer (c) & explanation
Statements 1 and 3 are correct (c). The National Biodiversity Authority (set up 2003 under the Biological Diversity Act, 2002, at Chennai) regulates access to Indian biological resources and associated traditional knowledge to check biopiracy (1). Anyone seeking a patent or other IPR based on Indian biological material needs its approval (3). Statement 2 is wrong: research on GM crops is regulated by the GEAC and the Review Committee on Genetic Manipulation, not the NBA. So (a), (b) and (d) fail.
Notice the cases: India fought patents on neem and turmeric, and the NBA backed action against Bt brinjal biopiracy (2011). The 2023 amendment eased rules for AYUSH and research, and requires approval at the time of grant of patent rather than filing.
Answer as per the official UPSC answer key.
Which one of the following groups of animals belongs to the category of endangered species?
Answer (a) & explanation
Option (a) is correct per UPSC's key. Option (a) lists only threatened animals: the Great Indian Bustard (Critically Endangered), musk deer and red panda (Endangered), and the Asiatic wild ass, treated as endangered in India; the Indian subspecies, the khur, is in Schedule I (the IUCN now lists the species as a whole as Near Threatened, so the grouping is loose). Each other option includes a common animal: cheetal and blue bull (nilgai) in (b) and (d), rhesus monkey in (c), and Hanuman langur in (d). So (b), (c) and (d) fail.
Notice the bustard's plight: fewer than 150 remain, mainly in Rajasthan; the Supreme Court has ordered undergrounding of power lines in its habitat. Trap: one common animal sinks an option.
Answer as per the official UPSC answer key.
What is the difference between the antelopes Oryx and Chiru?
Answer (a) & explanation
Option (a) is correct. The oryx is adapted to the hot, arid deserts of Africa and Arabia, with pale coats and water-saving physiology. The chiru (Tibetan antelope) lives in the cold, high-altitude steppes and semi-deserts of the Tibetan plateau and Ladakh. (b) is wrong: antelopes have horns, not antlers, and the chiru is poached for its fine wool (shahtoosh), not musk. (c) is wrong: the oryx is not found wild in India, and the chiru lives in Ladakh, not the north-east. (d) fails because (a) is correct.
Notice the conservation side: shahtoosh trade is banned under CITES, and the chiru is in Schedule I; its numbers recovered enough to be moved to Near Threatened in 2016. The Arabian oryx was reintroduced after extinction in the wild. Trap: musk belongs to musk deer.
Answer as per the official UPSC answer key.
Which of the following can be threats to the biodiversity of a geographical area?
- 1. Global warming
- 2. Fragmentation of habitat
- 3. Invasion of alien species
- 4. Promotion of vegetarianism
Select the correct answer using the codes given below :
Answer (a) & explanation
Items 1, 2 and 3 are correct (a). The main threats to biodiversity are habitat loss and fragmentation (2), invasive alien species such as Lantana and Prosopis in India (3), climate change (1), pollution and over-exploitation. Item 4 is wrong: vegetarianism needs less land and water than meat-heavy diets, so it reduces pressure on habitats; it is not a threat. So (b), (c) and (d) fail.
Notice the framework: E.O. Wilson's 'HIPPO' (habitat loss, invasive species, pollution, population, over-harvesting). The IPBES assessment (2019) said about 1 million species face extinction. India's National Biodiversity Strategy and Action Plan (2024) aligns with the Kunming-Montreal 30x30 target. Trap: item 4 is a lifestyle choice dressed up as a threat.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Black-necked crane
- 2. Cheetah
- 3. Flying squirrel
- 4. Snow leopard
Which of the above are naturally found in India?
Answer (b) & explanation
Items 1, 3 and 4 are correct (b). The black-necked crane breeds in Ladakh and winters in Arunachal's Tawang area and Bhutan (1). Flying squirrels live in the Western Ghats, the Himalaya and the north-east (3). The snow leopard lives in the high Himalaya of Ladakh, Himachal, Uttarakhand, Sikkim and Arunachal (4). Item 2 is wrong: the Asiatic cheetah was declared extinct in India in 1952, so it was not naturally found in 2012. So (a), (c) and (d) fail.
Notice the update: African cheetahs were brought to Kuno (MP) from September 2022 under Project Cheetah, and some were moved to Gandhi Sagar in 2025. India's first snow leopard survey (2023) counted about 718. Trap: today's cheetahs are introduced, not native.
Answer as per the official UPSC answer key.
Vultures which used to be very common in Indian countryside some years ago are rarely seen nowadays. This is attributed to
Answer (b) & explanation
A drug used for treating cattle is correct (b). Vultures feeding on carcasses of cattle treated with the painkiller diclofenac died of kidney failure and visceral gout. More than 95% of India's Gyps vultures (white-rumped, long-billed, slender-billed) were lost between the 1990s and 2000s. (a), (c) and (d) are wrong: invasive species, food shortage and a disease were not the main cause; carcasses were plentiful.
Notice the response: veterinary diclofenac was banned in 2006, and in 2023 India also banned aceclofenac and ketoprofen for animals. The Vulture Action Plan 2020–25 set up breeding centres, such as Pinjore in Haryana, and safe zones. Without vultures, feral dogs and rabies rose. International Vulture Awareness Day is the first Saturday of September. Trap: the cause was human-made, not natural.
Answer as per the official UPSC answer key.
Protected areas and conservation 3
With reference to the wetlands of India, consider the following statements :
- 1. The country’s total geographical area under the category of wetlands is recorded more in Gujarat as compared to other States.
- 2. In India, the total geographical area of coastal wetlands is larger than that of inland wetlands.
Which of the statements given above is/are correct?
Answer (a) & explanation
Statement 1 only is correct (a). The National Wetland Atlas (ISRO's Space Applications Centre, 2011) found that Gujarat has the largest wetland area of any state, about a fifth of India's total, thanks to the Rann of Kutch, the Gulf of Khambhat and other coastal flats (1). Statement 2 is wrong: for India as a whole, inland wetlands (about 69%) are larger than coastal wetlands (about 27%). So (b), (c) and (d) fail.
Notice the Ramsar count: India has about 90+ Ramsar sites, the most in Asia, with Tamil Nadu having the most sites; the largest single site is the Sundarbans. The Wetlands (Conservation and Management) Rules, 2017 govern them, and Amrit Dharohar (2023) promotes them. Trap: Gujarat's coastal wetlands are huge, but nationally inland wetlands lead.
Gujarat sounds like a dry State, so statement 1 looks wrong; the Rann of Kutch and the Gulf of Khambhat make it the top wetland State.
Answer as per the official UPSC answer key.
Consider the following protected areas :
- 1. Bandipur
- 2. Bhitarkanika
- 3. Manas
- 4. Sunderbans
Which of the above are declared Tiger Reserves?
Answer (b) & explanation
Bandipur, Manas and Sundarbans are correct (b). Bandipur (Karnataka), Manas (Assam) and Sundarbans (West Bengal) were among the first nine Project Tiger reserves of 1973–74. Item 2 is wrong: Bhitarkanika (Odisha) is a mangrove national park and Ramsar site famous for saltwater crocodiles, not a tiger reserve. So (a), (c) and (d) fail.
Notice the current count: India has 58 tiger reserves (the latest being Madhav, MP, in March 2025). The 2022 estimate counted at least 3,167 tigers (about 3,682 by full analysis), about 75% of the world's wild tigers. Odisha's tiger reserves are Similipal and Satkosia. Trap: Bhitarkanika sounds like a big Odisha reserve but is for crocodiles.
Bhitarkanika is famous enough to look like a Tiger Reserve, but it is known for crocodiles and mangroves, not tigers.
Answer as per the official UPSC answer key.
In which one among the following categories of protected areas in India are local people *not* allowed to collect and use the biomass?
Answer (b) & explanation
National Parks is correct (b). National Parks have the strictest protection under the Wildlife (Protection) Act, 1972: no grazing and no collection of forest produce or biomass; rights are settled and extinguished. (d) is wrong: sanctuaries may allow some regulated rights of local people. (a) is wrong: biosphere reserves have buffer and transition zones where people live and use resources. (c) is wrong: Ramsar wetlands follow the 'wise use' principle and allow sustainable use.
Notice the numbers: India has about 106 national parks and over 570 sanctuaries. The Forest Rights Act, 2006 also recognises community rights, which creates tension in critical wildlife habitats. Conservation and community reserves (2002 amendment) are other categories. Trap: only the core legal category bans all collection.
Answer as per the official UPSC answer key.
Climate change and international conventions 4
If National Water Mission is properly and completely implemented, how will it impact the country?
- 1. Part of the water needs of urban areas will be met through recycling of waste-water.
- 2. The water requirements of coastal cities with inadequate alternative sources of water will be met by adopting appropriate technologies that allow for the use of ocean water.
- 3. All the rivers of Himalayan origin will be linked to the rivers of peninsular India.
- 4. The expenses incurred by farmers for digging bore-wells and for installing motors and pump-sets to draw ground-water will be completely reimbursed by the Government.
Select the correct answer using the codes given below :
Answer (b) & explanation
Statements 1 and 2 are correct (b). The National Water Mission is one of the eight missions of the National Action Plan on Climate Change (2008). It aims to raise water-use efficiency by 20%, including recycling of waste water in cities (1) and desalination and other technologies for coastal cities short of water (2). Statement 3 is wrong: interlinking of rivers is a separate programme, not part of the mission. Statement 4 is wrong: the mission does not reimburse farmers' bore-well and pump costs; it seeks to curb groundwater overuse. So (a), (c) and (d) fail.
Notice the related schemes: Atal Bhujal Yojana (2019) for groundwater, Jal Shakti Abhiyan: Catch the Rain, and the Ken–Betwa link, the first project under the national river-linking plan.
Answer as per the official UPSC answer key.
The acidification of oceans is increasing. Why is this phenomenon a cause of concern?
- 1. The growth and survival of calcareous phytoplankton will be adversely affected.
- 2. The growth and survival of coral reefs will be adversely affected.
- 3. The survival of some animals that have phytoplanktonic larvae will be adversely affected.
- 4. The cloud seeding and formation of clouds will be adversely affected.
Which of the statements given above is/are correct?
Answer (a) & explanation
Statements 1, 2 and 3 are correct per UPSC's key (a), but item 4 is arguable. The sea absorbs CO₂ and forms carbonic acid, lowering pH and the carbonate that organisms need to build calcium carbonate shells and skeletons. This harms calcareous phytoplankton such as coccolithophores (1), coral reefs (2), and animals such as oysters and sea urchins with planktonic larval stages (3). Item 4: some plankton release dimethyl sulphide, which seeds clouds, so acidification may indirectly affect clouds; UPSC treated this as not established.
Notice the numbers: surface ocean pH has fallen from about 8.2 to 8.1 since industrialisation, about a 30% rise in acidity. A 2025 study said ocean acidification has crossed its planetary boundary. Trap: 'acid' does not mean the sea is actually acidic; it stays alkaline.
Answer as per the official UPSC answer key.
The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs
Answer (d) & explanation
The infrared part is correct (d). Carbon dioxide lets visible sunlight pass, but it absorbs infrared (heat) radiation, mainly the long-wave radiation given off by the warmed Earth, and some of the infrared in sunlight. It then re-radiates this heat in all directions, including back to the surface: the greenhouse effect. (a) is wrong: CO₂ does not absorb water vapour. (b) is wrong: ultraviolet is absorbed mainly by ozone in the stratosphere. (c) is wrong: CO₂ is transparent to most visible light.
Notice the numbers: CO₂ has risen from about 280 ppm before industrialisation to over 420 ppm, and 2024 was the first calendar year above 1.5°C of warming. Water vapour is the largest greenhouse gas, and methane is far stronger per molecule. Trap: the question says 'solar radiation', but the key effect is on the Earth's own infrared.
Answer as per the official UPSC answer key.
Consider the following agricultural practices :
- 1. Contour bunding
- 2. Relay cropping
- 3. Zero tillage
In the context of global climate change, which of the above helps/help in carbon sequestration/storage in the soil?
Answer (b) & explanation
Zero tillage only is correct per UPSC's key (b), though the key is arguable. Zero tillage leaves the soil undisturbed and keeps crop residue on top, so soil organic carbon builds up instead of being oxidised to CO₂ (3). Contour bunding mainly checks soil erosion on slopes (1); by keeping topsoil and moisture in place it can help retain carbon indirectly, so some argue for (c). Relay cropping, sowing a second crop before the first is harvested, mainly uses the season fully (2). UPSC chose the practice whose direct aim is carbon storage.
Notice the related tools: Happy Seeder machines allow sowing into rice stubble in Punjab, cutting stubble burning. Cover crops, agroforestry and biochar also store soil carbon. The '4 per 1000' initiative (COP21) promotes soil carbon. Trap: erosion control is not the same as sequestration.
Answer as per the official UPSC answer key.
Pollution, environmental laws and green technology 3
The National Green Tribunal Act, 2010 was enacted in consonance with which of the following provisions of the Constitution of India?
- 1. Right to healthy environment, construed as a part of Right to life under Article 21
- 2. Provision of grants for raising the level of administration in the Scheduled Areas for the welfare of Scheduled Tribes under Article 275(1)
- 3. Powers and functions of Gram Sabha as mentioned under Article 243(A)
Select the correct answer using the codes given below :
Answer (a) & explanation
Statement 1 only is correct (a). The NGT Act, 2010 preamble says the right to a healthy environment is part of the right to life under Article 21, and that the Act gives effect to India's commitments at the 1992 Rio Earth Summit. (2) is wrong: Article 275(1) provides grants to states for tribal welfare and Scheduled Areas; it has nothing to do with the tribunal. (3) is wrong: Article 243A concerns the Gram Sabha's powers. So (b), (c) and (d) fail.
Notice the tribunal: the NGT's principal bench is in New Delhi, with zonal benches at Bhopal, Pune, Kolkata and Chennai. It must decide cases within six months, follows the polluter pays and precautionary principles, and appeals go to the Supreme Court. India was the third country, after Australia and New Zealand, with such a body.
Answer as per the official UPSC answer key.
Lead, ingested or inhaled, is a health hazard. After the addition of lead to petrol has been banned, what still are the sources of lead poisoning?
- 1. Smelting units
- 2. Pens and pencils
- 3. Paints
- 4. Hair oils and cosmetics
Select the correct answer using the codes given below :
Answer (b) & explanation
Smelting units and paints are correct per UPSC's key (b), but the key is doubtful on item 4. Lead still comes from smelters and battery-recycling units (1) and from lead-based paints (3). Item 2 is wrong: 'pencil lead' is actually graphite mixed with clay. Item 4 is the doubt: some traditional cosmetics such as sindoor, surma/kohl and certain hair dyes have been found to contain lead, so (a)-type answers including 4 are arguable; UPSC left them out. So (c) fails on any reading.
Notice the rules: India's 2016 rules cap lead in household paint at 90 ppm. A 2020 UNICEF report estimated about 27.5 crore Indian children have high blood lead. Trap: the word 'lead' in pencils.
Answer as per the official UPSC answer key.
Consider the following statements :
Chlorofluorocarbons, known as ozone-depleting substances, are used
- 1. in the production of plastic foams
- 2. in the production of tubeless tyres
- 3. in cleaning certain electronic components
- 4. as pressurizing agents in aerosol cans
Which of the statements given above is/are correct?
Answer (c) & explanation
Statements 1, 3 and 4 are correct (c). Chlorofluorocarbons were used as blowing agents for plastic foams (1), as solvents to clean electronic circuit boards (3), as aerosol propellants (4) and as refrigerants. Statement 2 is wrong: CFCs are not used to make tubeless tyres. So (a), (b) and (d) fail.
Notice the treaties: the Vienna Convention (1985) and Montreal Protocol (1987) phased out CFCs, and the Kigali Amendment (2016) now phases down their substitutes, HFCs, which are powerful greenhouse gases; India must cut HFCs from 2032. The ozone hole over Antarctica is expected to heal by about 2066. World Ozone Day is 16 September. Trap: tyres sound industrial but have no CFC link.
Answer as per the official UPSC answer key.
All years by topic
Every question from 2011 to 2026, grouped by syllabus topic, with year-wise trends.