Artificial way of causing rainfall to reduce air pollution makes use of

1. A. silver iodide and potassium iodide
2. B. silver nitrate and potassium iodide
3. C. silver iodide and potassium nitrate
4. D. silver nitrate and potassium chloride

Answer: A

Explanation

Artificial rainfall, commonly known as cloud seeding, is a weather modification technique used to increase precipitation or reduce air pollution. The most common substances used for cloud seeding are silver iodide (AgI) and, less frequently, potassium iodide (KI). These compounds are dispersed into clouds, where they act as ice nuclei or cloud condensation nuclei. They provide a surface for water vapor to condense or freeze upon, facilitating the formation of ice crystals or water droplets that can then grow large enough to fall as rain or snow. Other substances like dry ice (solid carbon dioxide) can also be used. The use of such technologies for environmental management, especially in addressing air pollution, is a relevant topic for UPSC Environment & Ecology.