Delhi Cloud Seeding Pilot: Artificial Rain Against Pollution
Why in the news
Delhi prepared its first cloud seeding pilot, working with IIT-Kanpur and the Department of Environment, to tackle heavy winter pollution through artificial rain.
Why Delhi needs it
- PM2.5 and PM10 often fall in the ‘severe’ category.
- Sources: vehicle and industrial emissions, construction dust, stubble burning in nearby states and adverse weather.
- Poor air harms breathing and heart health.
What is cloud seeding
- A weather modification method that spreads substances into clouds to trigger rain or snow.
- Chemicals: silver iodide, potassium iodide, dry ice, rock salt.
- They serve as condensation or ice nuclei, speeding droplet formation and washing out pollutants.
Applications
- Settling airborne PM2.5 and PM10 during high AQI spells.
- Raising water in reservoirs and helping drought-prone farms.
- Ecosystem, farm and weather-stability gains.
- Fewer respiratory illnesses.
Types of cloud seeding
| Type | Method |
|---|---|
| Static | Ice-forming nuclei added to cold clouds; supercooled water becomes ice crystals |
| Dynamic | Boosts vertical air currents to grow clouds; more complex |
| Hygroscopic | Fine salt particles enlarge droplets; suits warm, moist clouds |
| Glaciogenic | Forms ice in supercooled liquid clouds; used in mountains for snowpack, drought relief and pollution control |
Exam angle
- UPSC Prelims 2025 asked which substances are used for artificial rain to cut air pollution; the answer was silver iodide and potassium iodide.
- Partner institute: IIT-Kanpur.