UPSC Prelims 2012
Environment & Ecology Previous Year Questions (PYQs)
Explore 19 solved UPSC Prelims 2012 Environment & Ecology questions with detailed step-by-step bilingual solutions, option analysis, and answer keys.
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?
- Smelting units
- Pens and pencils
- Paints
- Hair oils and cosmetics
Detailed Explanation:
✅ Statement 1 – Correct: Smelting units release lead particles into air and soil during ore processing, making them a major source of environmental lead contamination.
❌ Statement 2 – Incorrect: Pencils contain graphite (carbon) and clay, not lead; the term "lead" is a historical misnomer.
✅ Statement 3 – Correct: Lead-based paints remain a significant hazard as deteriorating paint releases lead dust and chips that can be inhaled or ingested.
❌ Statement 4 – Incorrect: While some traditional cosmetics (surma/kohl) may contain lead, standard hair oils and modern cosmetics are not primary sources of lead poisoning.
If the National Water Mission is properly and completely implemented, how will it impact the country?
- Part of the water needs of urban areas will be met through recycling of wastewater.
- 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.
- All the rivers of Himalayan origin will be linked to the rivers of peninsular India.
- The expenses incurred by farmers for digging bore-wells and for installing motors and pump sets to draw groundwater will be completely reimbursed by the Government.
Select the correct answer using the codes given below:
Detailed Explanation:
✅ Statement 1 – Correct: The National Water Mission (NWM) explicitly includes urban water recycling and reuse as a key strategy to meet part of the water needs of urban areas and reduce dependency on freshwater sources.
✅ Statement 2 – Correct: The NWM promotes adoption of desalination technologies for coastal cities facing water scarcity, particularly where alternative freshwater sources are inadequate.
❌ Statement 3 – Incorrect: The interlinking of rivers is a separate project under the National Perspective Plan, not part of the NWM's mandate, which focuses on water conservation and efficient use.
❌ Statement 4 – Incorrect: The NWM emphasizes sustainable groundwater management and promotes efficiency, but does not include financial reimbursement schemes for farmers' bore-well and pump-set expenses.
Consider the following areas:
- Bandipur
- Bhitarkanika
- Manas
- Sunderbans
Which of the above are Tiger Reserves?
Detailed Explanation:
Bandipur (Karnataka) – Declared a Tiger Reserve in 1973 under Project Tiger; one of India's first nine tiger reserves.
Bhitarkanika (Odisha) – A wetland and mangrove ecosystem known for saltwater crocodiles and bird diversity; NOT a Tiger Reserve.
Manas (Assam) – A Tiger Reserve, National Park, UNESCO World Heritage Site, Elephant Reserve, and Biosphere Reserve.
Sunderbans (West Bengal) – A Tiger Reserve famous for Royal Bengal Tigers adapted to mangrove habitat; also a UNESCO World Heritage Site.
Therefore, 1, 3 and 4 only are Tiger Reserves.
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What is the difference between the antelopes Oryx and Chiru?
Detailed Explanation:
✅ Statement 1 – Correct: Oryx is a genus of four large antelope species adapted to hot and arid areas of Africa and Arabia, whereas Chiru (Tibetan antelope) is adapted to steppes and semi-desert areas of cold high mountains on the Tibetan Plateau.
❌ Statement 2 – Incorrect: Oryx has horns (not antlers) but is not primarily poached for them; Chiru is poached for its fine underfur (shahtoosh), not musk.
❌ Statement 3 – Incorrect: Oryx does not exist in western India naturally (found in Africa/Arabia); Chiru is found in Ladakh and high-altitude regions, not north-east India.
In which one among the following categories of protected areas in India are local people not allowed to collect and use the biomass?
Detailed Explanation:
National Parks in India prohibit local people from collecting or using biomass as per the Wildlife Protection Act, 1972.
Biosphere Reserves (buffer & transition zones), Wildlife Sanctuaries (with Chief Wildlife Warden's permission), and Ramsar Wetlands (site-specific regulations) allow regulated biomass collection by local communities under certain conditions.
Government of India encourages the cultivation of ‘sea buckthorn’. What is the importance of this plant?
- It helps in controlling soil erosion and preventing desertification.
- It is a rich source of biodiesel.
- It has nutritional value and is well-adapted to live in cold areas of high altitudes.
- Its timber is of great commercial value.
Detailed Explanation:
✅ Statement 1 – Correct: Sea buckthorn is a soil-binding plant with extensive root systems that effectively control soil erosion and prevent desertification, particularly in fragile Himalayan ecosystems.
❌ Statement 2 – Incorrect: Sea buckthorn is not a source of biodiesel; it is cultivated for its berries, leaves, and medicinal/nutritional products, not biofuel production.
✅ Statement 3 – Correct: The plant has high nutritional value with berries rich in vitamins C, E, carotenoids, and omega fatty acids, and thrives in cold, high-altitude regions like Ladakh and Spiti (-40°C to +40°C tolerance).
❌ Statement 4 – Incorrect: Sea buckthorn is a shrub, not a timber tree; its commercial value lies in fruits, cosmetics, pharmaceuticals, not timber.
How does the National Biodiversity Authority (NBA) help in protecting Indian agriculture?
- NBA checks the biopiracy and protects indigenous and traditional genetic resources.
- NBA directly monitors and supervises the scientific research on genetic modification of crop plants.
- Application for Intellectual Property Rights related to genetic/biological resources cannot be made without the approval of the NBA.
Detailed Explanation:
✅ Statement 1 – Correct: NBA checks biopiracy and protects indigenous and traditional genetic resources under the Biological Diversity Act, 2002.
❌ Statement 2 – Incorrect: NBA does not directly monitor genetic modification research on crops; this is done by GEAC (Genetic Engineering Appraisal Committee) under the Ministry of Environment, Forest and Climate Change.
✅ Statement 3 – Correct: IPR applications related to biological resources require prior approval from NBA as per Section 6 of the Biological Diversity Act.
Which of the following can be threats to the biodiversity of a geographical area?
- Global warming
- Fragmentation of habitat
- Invasion of alien species
- Promotion of vegetarianism
Detailed Explanation:
✅ Statement 1 – Correct: Global warming causes climate change, leading to habitat loss, altered precipitation patterns, and species extinction due to inability to adapt to rising temperatures.
✅ Statement 2 – Correct: Habitat fragmentation divides large habitats into smaller, isolated patches, reducing genetic diversity, disrupting migration corridors, and making populations more vulnerable to extinction.
✅ Statement 3 – Correct: Invasive alien species (e.g., Lantana camara, Water hyacinth) outcompete native species for resources, disrupt ecological balance, and cause local extinctions.
❌ Statement 4 – Incorrect: Promotion of vegetarianism reduces pressure on ecosystems by decreasing demand for livestock farming, which causes deforestation and habitat destruction—thus it benefits biodiversity, not threatens it.
Which one of the following groups of animals belongs to the category of endangered species?
Detailed Explanation:
Great Indian Bustard is Critically Endangered (IUCN), found in Rajasthan and Gujarat; Musk Deer is Endangered, hunted for musk pods in Himalayas; Red Panda is Endangered, native to eastern Himalayas; Asiatic Wild Ass (Khur) is Near Threatened (IUCN) but Schedule I species under Wildlife Protection Act, 1972.
Options 2, 3, and 4 are incorrect because they include Least Concern species: Cheetal, Blue Bull (Nilgai), Rhesus Monkey, and Hanuman Langur. Additionally, Saras Crane and Swamp Deer are Vulnerable, not Endangered.
The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere because it absorbs -
Detailed Explanation:
Carbon dioxide (CO₂) and other greenhouse gases absorb infrared radiation (heat) emitted by Earth's surface after it absorbs solar energy.
This trapped infrared radiation causes the greenhouse effect, gradually raising atmospheric temperature—not UV or all solar radiation, but specifically the long-wave infrared re-radiated from Earth.
Vultures which used to be very common in the Indian countryside some years ago are rarely seen nowadays. This is attributed to
Detailed Explanation:
Diclofenac, a non-steroidal anti-inflammatory drug (NSAID) used by cattle owners to treat livestock, caused the catastrophic decline of vulture populations in India.
Vultures feeding on carcasses of diclofenac-treated cattle suffered acute kidney failure, leading to a 99% population crash of three species (White-rumped, Indian, and Slender-billed vultures) between the 1990s and early 2000s. India banned veterinary diclofenac in 2006.
Biomass gasification is considered to be one of the sustainable solutions to the power crisis in India. In this context, which of the following statements is/are correct?
- Coconut shells, groundnut shells and rice husk can be used in biomass gasification.
- The combustible gases generated from biomass gasification consist of hydrogen and carbon dioxide only.
- The combustible gases generated from biomass gasification can be used for direct heat generation but not in internal combustion engines.
Detailed Explanation:
✅ Statement 1 – Correct: Coconut shells, groundnut shells, and rice husk are excellent agricultural residues and biomass feedstock for gasification due to their high carbon content and low moisture.
❌ Statement 2 – Incorrect: The syngas (synthesis gas) from biomass gasification primarily contains carbon monoxide (CO), hydrogen (H₂), methane (CH₄), and carbon dioxide (CO₂), not just hydrogen and carbon dioxide.
❌ Statement 3 – Incorrect: Syngas from biomass gasification can be used for both direct heat generation and in internal combustion engines after proper cleaning and cooling to remove tar and particulates.
What would happen if phytoplankton of an ocean is completely destroyed for some reason?
- The ocean as a carbon sink would be adversely affected.
- The food chains in the ocean would be adversely affected.
- The density of ocean water would drastically decrease.
Detailed Explanation:
✅ Statement 1 – Correct: Phytoplankton perform photosynthesis and absorb atmospheric CO₂, converting it into organic carbon through carbon sequestration. Their destruction would severely impair the ocean's role as a carbon sink.
✅ Statement 2 – Correct: Phytoplankton form the base of marine food chains, being the primary producers consumed by zooplankton and small fish, which support larger marine organisms. Their complete destruction would collapse oceanic food webs.
❌ Statement 3 – Incorrect: Ocean water density is determined by temperature and salinity, not by the presence of microscopic phytoplankton. Their removal would have negligible impact on water density.
Consider the following kinds of organisms :
- Bat
- Bee
- Bird
Which of the above is/are pollinating agent/agents?
Detailed Explanation:
Pollinating agents are organisms that transfer pollen from male to female parts of flowers, enabling fertilization and seed production.
Bats (especially frugivorous and nectar-feeding species) pollinate tropical and desert plants while feeding on nectar, with pollen sticking to their fur.
Bees are the most efficient pollinators, collecting nectar and pollen for food and transferring pollen between flowers during foraging.
Birds (like hummingbirds, sunbirds, and honeyeaters) pollinate brightly colored, tubular flowers while feeding on nectar, with pollen adhering to their beaks and feathers.
All three organisms — bats, bees, and birds — are important pollinating agents in various ecosystems.
Consider the following:
- Black-necked crane
- Cheetah
- Flying squirrel
- Snow leopard
Which of the above are naturally found in India?
Detailed Explanation:
✅ Black-necked crane – Correct: Naturally found in Ladakh and Arunachal Pradesh (trans-Himalayan regions); migrates to India during winter.
❌ Cheetah – Incorrect: Declared extinct in India since 1952; the last three cheetahs were shot in Chhattisgarh (then part of Madhya Pradesh) in 1947. Recent reintroductions in Kuno National Park (2022) are not naturally found populations.
✅ Flying squirrel – Correct: Several species naturally occur in India, including Indian Giant Flying Squirrel (Western Ghats) and Red Giant Flying Squirrel (Northeast forests).
✅ Snow leopard – Correct: Found in high-altitude Himalayan and trans-Himalayan regions (Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, Arunachal Pradesh) at elevations above 3,000–5,500 meters.
The acidification of oceans is increasing. Why is this phenomenon a cause of concern?
- The growth and survival of calcareous phytoplankton will be adversely affected.
- The growth and survival of coral reefs will be adversely affected.
- The survival of some animals that have phytoplanktonic larvae will be adversely affected.
- The cloud seeding and formation of clouds will be adversely affected.
Detailed Explanation:
✅ Statement 1 – Correct: Calcareous phytoplankton (like coccolithophores) need carbonate ions to build calcium carbonate shells; ocean acidification reduces these ions, impairing their calcification, growth, and survival.
✅ Statement 2 – Correct: Coral reefs are made of calcium carbonate; increased acidity lowers the saturation state, making it harder for corals to build skeletons and can cause reef dissolution.
✅ Statement 3 – Correct: Many marine invertebrates (mollusks, echinoderms) have phytoplanktonic larvae sensitive to seawater chemistry changes; acidification impairs their development and shell formation, increasing mortality.
❌ Statement 4 – Incorrect: While acidification may reduce dimethyl sulfide (DMS) production affecting cloud condensation nuclei, this is an indirect climatic feedback, not a primary direct concern for ocean ecosystems.
Consider the following statements: Chlorofluorocarbons, known as ozone-depleting substances, are used
- in the production of plastic foams
- in the production of tubeless tyres
- in cleaning certain electronic components
- as pressurizing agents in aerosol cans
Which of the statements given above is/are correct?
Detailed Explanation:
✅ Statement 1 – Correct: CFCs were widely used as blowing agents in the production of plastic foams (polystyrene, polyurethane) for insulation and packaging.
❌ Statement 2 – Incorrect: Tubeless tyres are manufactured through vulcanization using sulfur; CFCs have no role in tyre production.
✅ Statement 3 – Correct: CFC-113 was extensively used as a solvent for cleaning electronic components and circuit boards due to its non-flammable, residue-free properties.
✅ Statement 4 – Correct: CFCs served as propellants/pressurizing agents in aerosol cans (hairsprays, deodorants) before being phased out under the Montreal Protocol.
The Millennium Ecosystem Assessment describes the following major categories of ecosystem services: provisioning, supporting, regulating, preserving, and cultural. Which one of the following is a supporting service?
Detailed Explanation:
Millennium Ecosystem Assessment (2005) classifies ecosystem services into four categories: Provisioning, Regulating, Supporting, and Cultural.
Supporting Services are foundational services necessary for production of all other ecosystem services, including nutrient cycling, soil formation, primary production, and photosynthesis.
Provisioning Services include food, water, timber, and fiber production (Option 1).
Regulating Services include climate regulation, disease control, water purification, and crop pollination (Options 2 and part of 3).
Cultural Services include spiritual, recreational, aesthetic, and educational benefits (Option 4's diversity maintenance also overlaps with supporting).
Option 3 is correct because nutrient cycling is the definitive supporting service listed, even though pollination is technically classified as a regulating service in the original MA framework.
With reference to the wetlands of India, consider the following statements :
- The country’s total geographical area under the category of wetlands is recorded more in Gujarat as compared to other States.
- 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?
Detailed Explanation:
✅ Statement 1 – Correct: Gujarat has the largest geographical area under wetlands in India, accounting for approximately 17.56% of the country's total wetland area, followed by West Bengal, Andhra Pradesh, and Uttar Pradesh.
❌ Statement 2 – Incorrect: Inland wetlands account for 69% of India's total wetland area, while coastal wetlands constitute only 27%, making inland wetlands significantly larger than coastal wetlands.
UPSC Prelims 2012 - Environment & Ecology Chapter-wise Distribution
Biodiversity and Conservation
7 Qs (36.8%)Environmental Pollution
2 Qs (10.5%)Climate Change and Mitigation
2 Qs (10.5%)Environmental Governance in India
2 Qs (10.5%)Flora, Fauna and Protected Areas
2 Qs (10.5%)Fundamentals of Ecology
2 Qs (10.5%)Environmental Issues & Challenges
1 Qs (5.3%)Renewable Energy & Green Technologies
1 Qs (5.3%)UPSC Prelims 2012 - Environment & Ecology Questions FAQs
Q1 How many Environment & Ecology questions were asked in UPSC Prelims 2012?
Q2 What is the chapter-wise question distribution for Environment & Ecology in UPSC Prelims 2012?
- Biodiversity and Conservation: 7 questions (36.8%)
- Environmental Pollution: 2 questions (10.5%)
- Climate Change and Mitigation: 2 questions (10.5%)
- Environmental Governance in India: 2 questions (10.5%)
- Flora, Fauna and Protected Areas: 2 questions (10.5%)
- Fundamentals of Ecology: 2 questions (10.5%)
- Environmental Issues & Challenges: 1 questions (5.3%)
- Renewable Energy & Green Technologies: 1 questions (5.3%)