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

Correct Option

Artificial rainfall, commonly referred to as cloud seeding, is a weather modification technique aimed at increasing precipitation. This process involves dispersing substances into clouds to serve as cloud condensation nuclei (CCN) or ice nuclei. The primary agents used for this purpose are silver iodide (AgI) and, in some applications, potassium iodide (KI).

These compounds facilitate the condensation or freezing of supercooled water droplets within clouds, leading to the formation of larger water droplets or ice crystals. When these particles grow to a sufficient size, they fall as precipitation. This technique can be employed to enhance water resources, alleviate drought conditions, or temporarily reduce air pollution by washing particulate matter from the atmosphere.

Incorrect Options

• Silver nitrate (options 2 and 4) is not typically used as a cloud seeding agent for large-scale artificial rainfall induction. Its physical properties are less effective for ice nucleation compared to silver iodide, and it is generally more costly.
• Potassium nitrate (option 3) is not a recognized or commonly utilized compound for inducing artificial rainfall. Its chemical and physical characteristics do not align with the requirements for effective cloud condensation or ice nucleation.
• Potassium chloride (option 4) can act as a hygroscopic agent; however, for inducing precipitation in supercooled clouds, which is the mechanism often targeted for pollution reduction, silver iodide and potassium iodide are the more established and effective agents.