Why in the News?
The Delhi government is planning to trial cloud-seeding to trigger artificial rain to combat air pollution ahead of winters.
About Cloud Seeding:
- About: It is a microclimate management technique aimed at altering precipitation patterns by dispersing substances into clouds to stimulate rainfall or snowfall.
- Why it is used: It is used to mitigate hail, disperse fog, and either induce precipitation or prevent it from occurring in subsequent days.
- Techniques include:
- Static Cloud Seeding: Chemicals are introduced into cold clouds already containing supercooled water droplets, encouraging the formation of ice crystals.
- Hygroscopic Cloud Seeding: Salts are sprayed into the base of warm clouds to act as condensation nuclei, increasing the number and size of water droplets.
- Dynamic Cloud Seeding: This method involves boosting vertical air currents to enhance moisture passage through the clouds, leading to more rain.
- Common Cloud Seeding Chemicals:
- Silver iodide (AgI): Preferred for its ice-like crystalline properties.
- Potassium iodide (KI): Functions similarly to silver iodide.
- Dry ice (solid COâ‚‚): Used to rapidly cool cloud droplets, aiding rain formation.
- Liquid propane: Used in specific cloud types, effective at higher temperatures.
- Sodium chloride and calcium chloride: Used in hygroscopic (warm) cloud seeding methods.
- Bismuth tri-iodide (BiI₃): Sometimes used based on experimental or environmental considerations.
- Dispersion methods range from aircraft and ground-based generators to newer approaches like drones delivering electric charges or infrared laser pulses.
Limitations:Â
- Concerns persist regarding the potential accumulation of seeding agents in sensitive ecosystems, although detailed studies have shown negligible impacts.
- The chemicals used, such as silver iodide, may potentially damage the environment and cause health issues like iodine poisoning in high concentrations
| [UPSC 2025] Artificial way of causing rainfall to reduce air pollution makes use of:
(a) silver iodide and potassium iodide * (b) silver nitrate and potassium iodide (c) silver iodide and potassium nitrate (d) silver nitrate and potassium chloride |
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