UPSC Prelims 2023 · GS Paper I
Question 59: Environment and Ecology
Consider the following statements regarding mercury pollution :
- 1.Gold mining activity is a source of mercury pollution in the world.
- 2.Coal-based thermal power plants cause mercury pollution.
- 3.There is no known safe level of exposure to mercury.
How many of the above statements are correct?
AnswerUPSC’s answer is (b).
Gold mining, especially artisanal and small-scale mining that uses mercury to extract gold, is the largest source of mercury pollution worldwide, and coal-fired power plants release mercury when coal burns, so statements 1 and 2 are correct. Statement 3 is wrong: for mercury, health-based guidance values such as tolerable intakes for methylmercury exist, so UPSC does not accept a 'no known safe level' claim. The Minamata Convention aims to cut mercury use and emissions.
- 1. Gold mining is a major source of mercury pollution.
- 2. Coal-fired plants emit mercury.
- 3. Safe-intake guidance values exist for mercury, so the 'no safe level' claim is not accepted.
How you could have got this
No shortcut here: in a “how many” question, ruling out options doesn’t help. Every statement has to be judged.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Only one undercounts the true statements.
- (b) Correct: statements 1 and 2 hold.
- (c) Statement 3 is not accepted, so not all three.
- (d) Mining and coal are known sources, so not none.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2023, General Studies Paper I, Series A. The paper on upsc.gov.in.