Environment MCQs for UPSC Prelims

Q1. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. A pumped storage reservoir sited on karst terrain can suffer large losses of stored water.
  2. Karst develops where water dissolves soluble rocks such as limestone, widening cracks into conduits and caves.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q2. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. A pumped storage reservoir sited on karst terrain can suffer large losses of stored water.
  2. Karst develops where water dissolves soluble rocks such as limestone, widening cracks into conduits and caves.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q3. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. Replacing furnace oil with natural gas in an industrial furnace sharply reduces its sulphur dioxide emissions.
  2. Sulphur compounds present in raw natural gas are largely removed during processing, leaving only trace amounts in the gas that is supplied.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q4. With reference to blending ethanol into petrol in India, consider the following statements: Which of the statements given above is/are correct?

  1. Domestically produced ethanol blended into petrol displaces part of the crude oil that would otherwise be imported, saving foreign exchange.
  2. Higher blending ratios reduce how strongly the oil import bill responds to a given rise in global crude prices.
  3. For a given volume of ethanol blended, the foreign exchange saved is larger when global crude prices are higher.
  • A. 2 and 3 only
  • B. 1, 2 and 3
  • C. 1 only
  • D. 1 and 2 only

Q5. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. The National Green Tribunal is required under its parent statute to apply the polluter-pays principle, along with the precautionary principle and sustainable development, while deciding cases.
  2. Decisions of the National Green Tribunal are final, and no appeal against them lies before any court.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q6. Several units that manufactured a chrome-tanning chemical were shut down by the State Pollution Control Board for violating hazardous-waste rules. Years later, environmental compensation was levied on them for the contamination caused by their waste. In the light of the polluter-pays principle as applied in India, consider the following statements: Which of the statements given above is/are correct?

  1. The closure of a unit does not extinguish its liability for environmental damage caused by its past operations.
  2. Levying compensation for past violations serves, in part, to ensure that violating environmental norms does not turn out to be profitable.
  3. The polluter's liability extends to the cost of restoring the damaged environment and is not limited only to compensating affected persons.
  • A. 1, 2 and 3
  • B. 1 and 2 only
  • C. 1 and 3 only
  • D. 2 and 3 only

Q7. Suppose a drinking-water standard caps chromium at 0.05 mg/L, measured as total chromium (trivalent plus hexavalent), and only the hexavalent form is of serious health concern. Consider the following inferences: Which of the inferences given above is/are valid?

  1. Water that meets this standard cannot contain more than 0.05 mg/L of hexavalent chromium.
  2. Water that fails this standard must contain more than 0.05 mg/L of hexavalent chromium.
  3. Water can fail this standard even when its hexavalent chromium content alone is below 0.05 mg/L.
  • A. 1 and 3 only
  • B. 1, 2 and 3
  • C. 1 only
  • D. 2 and 3 only

Q8. Authorities plan to inject a chemical reducing agent into an aquifer contaminated with hexavalent chromium. If the treatment works as intended, which one of the following is the most likely outcome?

  • A. Chromium changes into a more soluble form that flowing groundwater flushes out of the aquifer faster.
  • B. Chromium changes into a volatile form that escapes from the groundwater into the atmosphere above.
  • C. Chromium changes into a less toxic form that tends to settle out of water and bind to the soil.
  • D. Chromium is broken down by the reagent into carbon dioxide, water and other harmless mineral salts.

Q9. With reference to chromium in drinking water, consider the following statements: Which of the statements given above is/are correct?

  1. Because trivalent chromium is regarded as a trace nutrient, the toxicity of chromium in drinking water does not depend on its oxidation state.
  2. A measurement of total chromium in water counts both the trivalent and the hexavalent forms, although the health hazard arises mainly from the hexavalent form.
  • A. 1 only
  • B. 2 only
  • C. Both 1 and 2
  • D. Neither 1 nor 2

Q10. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. Chromium leaching from dumps of chrome-tanning waste is far more likely to travel through aquifers to distant wells when it is in the hexavalent state than when it is in the trivalent state.
  2. Hexavalent chromium compounds are soluble and mobile in soil and water, whereas trivalent chromium tends to precipitate and bind strongly to mineral and organic surfaces.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q11. Consider the following facts: The National Green Tribunal took up a matter on its own on the basis of a newspaper report about hexavalent chromium in groundwater, and no application was filed by any person. It recorded that the report raised substantial issues of compliance with environmental norms, issued notices to fourteen authorities including the State Government, the National Mission for Clean Ganga and a medical institute, and asked them to file affidavits before the next hearing. Consider the following inferences: Which of the inferences given above can validly be drawn?

  1. Naming a medical institute as a respondent shows that the Tribunal has assumed jurisdiction over cases of medical negligence.
  2. The Tribunal can continue with the matter even if no affected resident ever joins the proceedings as a party.
  3. Every authority served with notice has thereby been held responsible for causing the contamination.
  4. By calling for affidavits before passing final orders, the Tribunal is giving the authorities an opportunity to be heard.
  • A. 2, 3 and 4 only
  • B. 2 and 4 only
  • C. 1, 2 and 4 only
  • D. 1 and 3 only

Q12. With reference to the power of the National Green Tribunal (NGT) to take up matters on its own (suo motu), consider the following statements: Which of the statements given above is/are correct?

  1. The NGT may start proceedings without any application when a civil dispute raises a substantial question relating to environment under the enactments listed in Schedule I of its Act.
  2. Once acting suo motu, the NGT may take up any question of public health, even one unconnected with the enactments listed in Schedule I of its Act.
  3. The suo motu power is expressly conferred by a provision of the NGT Act, a position the Union Government itself argued before the Supreme Court.
  • A. 2 and 3 only
  • B. 1, 2 and 3
  • C. 1 and 2 only
  • D. 1 only

Q13. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. Diverting untreated sewage away from a lake slows down the lake's eutrophication.
  2. Sewage accelerates eutrophication chiefly by raising the temperature of the lake water, which speeds up algal growth.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q14. With reference to eutrophication of a lake, consider the following statements: Which of the statements given above are correct?

  1. It is driven mainly by a rise in the concentration of nitrogen and phosphorus in the water.
  2. Dense algal growth on the surface reduces the light reaching submerged plants.
  3. Decomposition of the resulting dead algae raises the dissolved oxygen available in deeper water.
  4. Inputs such as sewage, detergents and fertilisers speed up a process that also occurs naturally as lakes age.
  • A. 1, 2 and 4 only
  • B. 2, 3 and 4 only
  • C. 1 and 3 only
  • D. 1, 2, 3 and 4

Q15. With reference to the jurisdiction of the National Green Tribunal (NGT) and of High Courts in environmental matters, consider the following statements: Which of the statements given above is/are NOT correct?

  1. The NGT hears civil cases raising a substantial question relating to the environment only where the question arises from implementing an enactment listed in Schedule I of the NGT Act, 2010.
  2. A High Court may issue directions under Article 226 to a government within its territory not only to enforce Fundamental Rights but also for any other purpose.
  3. The Wild Life (Protection) Act, 1972 is one of the enactments listed in Schedule I of the NGT Act, 2010.
  • A. 2 and 3 only
  • B. 3 only
  • C. 1 and 3 only
  • D. 1, 2 and 3

Q16. With reference to the National Plan for Conservation of Aquatic Eco-systems (NPCA), consider the following statements: Which of the statements given above is/are correct?

  1. The cost of projects under the scheme is shared between the Centre and the States rather than being borne wholly by the Centre.
  2. The Central share of project cost under the scheme is uniform across all States, including the North-Eastern States.
  3. The scheme aims at improving the biodiversity of lakes and wetlands in addition to improving their water quality.
  • A. 1 only
  • B. 1, 2 and 3
  • C. 1 and 3 only
  • D. 2 and 3 only

Q17. With reference to the July 2024 draft notification on the Western Ghats Ecologically Sensitive Area, consider the following statements: Which of the statements given above is/are correct?

  1. The draft does not confine the ESA to forest land; it extends to revenue villages that contain human habitation.
  2. The draft adopts the Gadgil panel's approach of treating the entire Western Ghats range as ecologically sensitive.
  • A. 1 only
  • B. 2 only
  • C. Both 1 and 2
  • D. Neither 1 nor 2

Q18. Consider the following assertion: An Ecologically Sensitive Area regime in the Western Ghats can help reduce landslide risk, and not merely conserve biodiversity. Which of the statements given above support/supports the assertion?

  1. The Kasturirangan High-Level Working Group recommended banning all mining, including quarrying, within the ESA.
  2. The July 2024 draft ESA notification was issued a day after the Wayanad landslides.
  3. The Kasturirangan High-Level Working Group recommended banning building and construction projects above a specified size within the ESA.
  • A. 2 and 3 only
  • B. 1 only
  • C. 1 and 3 only
  • D. 1, 2 and 3

Q19. In the context of the Keralam Legislative Assembly's resolution on the Western Ghats Ecologically Sensitive Area, consider the following statements: Which of the statements given above is/are correct?

  1. A resolution of a State Legislative Assembly urging the Union government to accept the State's proposal does not, by itself, bind the Union government when it finalises the notification.
  2. The power to issue the final Western Ghats ESA notification lies with the Union government, not with the governments of the States it covers.
  3. Because the ESA spans more than one State, its final notification must be ratified by the Legislatures of at least half of the States it covers.
  • A. 1 and 2 only
  • B. 2 and 3 only
  • C. 1, 2 and 3
  • D. 1 only

Q20. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. The Western Ghats are on the World Heritage List as a serial property made up of many separate component sites, not as one continuous area.
  2. The Western Ghats run through six Indian States, from Gujarat in the north to Kerala and Tamil Nadu in the south.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q21. With reference to the expert reports on protecting the Western Ghats, consider the following statements: Which of the statements given above is/are correct?

  1. The Kasturirangan High-Level Working Group placed the cultural landscape under a permit-based regime of graded restrictions.
  2. The Gadgil panel treated the entire Western Ghats as ecologically sensitive but varied the permitted activities by zone, according to ecological richness and land use.
  3. The Kasturirangan High-Level Working Group designed its ESA as a prohibitory regime aimed at the most destructive activities, such as mining and red-category industries.
  • A. 1, 2 and 3
  • B. 2 and 3 only
  • C. 3 only
  • D. 1 and 2 only

Q22. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. As of October 2026, the Ecologically Sensitive Area for the Western Ghats has been proposed only through successive draft notifications, and no final notification has been issued.
  2. A draft ESA notification cannot be finalised until the Legislative Assembly of each State concerned passes a resolution concurring with it.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q23. With reference to the process of declaring the Western Ghats an Ecologically Sensitive Area (ESA), consider the following statements: Which of the statements given above is/are correct?

  1. A draft ESA notification gives the public a fixed window to file objections before the Union government decides on the final notification.
  2. After the Supreme Court declined to entertain a petition against the Gadgil and Kasturirangan reports, the Union government was legally obliged to finalise the ESA notification.
  3. A fresh draft ESA notification can supersede an earlier draft that was never finalised.
  • A. 1 only
  • B. 1, 2 and 3
  • C. 2 and 3 only
  • D. 1 and 3 only

Q24. Compared with surveillance based on clinical isolates collected from hospitals, wastewater-based surveillance of antimicrobial resistance is distinctive mainly because it

  • A. yields patient-level resistance profiles that guide individual antibiotic choices
  • B. measures resistance among hospital patients but not in the wider community
  • C. captures resistance carried by people who never seek care or get tested
  • D. detects resistance only after hospitals report a rise in treatment failures

Q25. If the apex predator is lost from a forest ecosystem in which it was the main regulator of large herbivores, which of the following is the most likely initial chain of effects?

  • A. An increase in herbivore density, followed by heavier grazing pressure on vegetation
  • B. A decrease in mid-sized predators, followed by a rise in their small prey
  • C. A decrease in herbivore density, followed by recovery of the understorey vegetation
  • D. An increase in primary productivity, followed by a rise in herbivore density

Q26. Consider the following facts: (i) India's tiger estimate rose across the 2014, 2018 and 2022 cycles; (ii) more than three-fourths of India's tigers are found within protected areas; (iii) a genetic study found tigers of one western Indian reserve to be nearly twice as inbred as central Indian tigers. Which of the following inferences can validly be drawn from the above facts?

  1. A rising national tiger count does not by itself ensure the genetic health of every local tiger population.
  2. Levels of inbreeding are broadly uniform across India's tiger populations.
  3. Because most tigers live within protected areas, tigers outside them are too few to matter for long-term conservation.
  • A. 2 and 3 only
  • B. 1 and 3 only
  • C. 1 and 2 only
  • D. 1 only

Q27. A tiger population confined to a single reserve has become small and cut off from other tiger populations. Consider the following statements about the likely consequences and remedies: Which of the statements given above are correct?

  1. Mating between closely related individuals becomes more frequent, raising the level of inbreeding.
  2. Restoring forest corridors to a larger tiger population would tend to restore genetic variation through gene flow.
  3. Strict protection that lets tiger numbers grow within the reserve is by itself sufficient to remove the genetic risk.
  4. Bringing in tigers from another population ('genetic rescue') is a recognised option when corridor restoration is too slow.
  • A. 1 and 2 only
  • B. 2, 3 and 4 only
  • C. 1, 2 and 4 only
  • D. 1, 3 and 4 only

Q28. Consider the following assertion: Indian law on protected areas has moved away from a purely 'fortress' model of conservation that treats local people only as a threat to be excluded. Which of the statements given below support/supports the above assertion?

  1. More than three-fourths of India's tigers are found within protected areas.
  2. Notification of a critical wildlife habitat under the Forest Rights Act requires consultation with the Gram Sabha and the affected persons.
  3. Relocation of people from core/critical tiger habitat is to be carried out only on a voluntary basis.
  • A. 2 and 3 only
  • B. 1, 2 and 3
  • C. 3 only
  • D. 1 and 2 only

Q29. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. The terms 'critical wildlife habitat' and 'critical tiger habitat' originate in two different statutes.
  2. The Forest Rights Act, 2006 was enacted as an amendment inserting a new chapter into the Wildlife (Protection) Act, 1972.
  • 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 incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q30. With reference to the institutional framework for tiger conservation in India, consider the following statements: Which of the statements given above is/are correct?

  1. The National Tiger Conservation Authority derives its existence from a statute, the Wildlife (Protection) Act, 1972 as amended in 2006, and not merely from an executive order.
  2. Project Tiger predates the National Tiger Conservation Authority and continues to run as a Centrally Sponsored Scheme.
  • A. 1 only
  • B. 2 only
  • C. Both 1 and 2
  • D. Neither 1 nor 2