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

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Silver iodide and potassium iodide Quick Verdict: Cloud seeding to artificially induce rain uses chemicals like silver iodide and potassium iodide to act as condensation nuclei. While this weather modification technique is often proposed to wash down severe air pollution, its success depends entirely on pre-existing, moisture-rich clouds—a condition rarely met during the dry winter months when smog is at its worst. Thematic Discussion: Cloud Seeding and Pollution Control The Science of Artificial Rain: Cloud seeding involves spraying chemicals (via aircraft or rockets) into moisture-laden clouds to produce artificial rainfall. These chemicals—usually silver iodide (AgI) and sometimes potassium iodide (KI)—act as artificial nuclei. Water vapour condenses around these injected particles into droplets, eventually growing heavy enough to fall as rain. The Limitation of Cloud Types: This rapid condensation requires specific "hygroscopic" clouds, which already contain abundant liquid water and respond effectively to the extra chemical nuclei. These moisture-rich clouds are common during pre- and post-monsoon periods but are largely absent during the winter when skies are naturally clear. Global and Indian Precedents: Global: Countries like China, the UAE, and the US have utilized similar methods for drought management and pollution control (such as washing suspended PM2.5 from the air), though with mixed results. India: India has experimented with cloud seeding since the 1950s, primarily as a drought management tool. States including Tamil Nadu, Karnataka, Maharashtra, and Andhra Pradesh have historically undertaken seeding operations to augment rainfall in water-scarce regions. The Delhi Experiment (October 2025): Recently, interest in cloud seeding shifted toward controlling urban air pollution. On October 28, 2025, the Delhi Government, in collaboration with IIT Kanpur, conducted cloud seeding trials to bring relief from the toxic post-Diwali smog. However, it failed to produce rain because Delhi’s pollution peaks during late autumn and winter, a period characterized by extremely low atmospheric humidity and shallow clouds. Long-Term Efficacy: Even if cloud seeding succeeds in inducing rain, the improvement in air quality is strictly short-lived. Rain can temporarily wash suspended pollutants out of the air, but unless the actual emission sources are curbed, the smog quickly returns. Consequently, experts heavily doubt the efficacy and sustainability of cloud seeding as a long-term pollution control measure.