UPSC Prelims 2025 · GS Paper I
Question 85: Environment and Ecology
Artificial way of causing rainfall to reduce air pollution makes use of
AnswerThe answer is (a).
Artificial rain, or cloud seeding, spreads tiny particles into clouds so that water droplets or ice crystals form around them and fall as rain. The usual seeding agents are silver iodide, whose crystal structure resembles ice and so makes a good nucleus, together with salts such as potassium iodide, and sometimes sodium chloride or dry ice. It is tried to bring rain that washes pollutants from the air. Silver nitrate with potassium iodide, or the nitrate and chloride combinations, are not the standard agents.
Why each option is right or wrong
- (a) Right: silver iodide and potassium iodide are the standard seeding agents.
- (b) Wrong: silver nitrate is not the usual seeding agent.
- (c) Wrong: potassium nitrate is not a standard seeding agent.
- (d) Wrong: silver nitrate and potassium chloride are not the usual agents.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2025, General Studies Paper I, Series A. The paper on upsc.gov.in.