• Cloud seeding is a kind of weather modification technology to create artificial rainfall.
• It works only when there are enough pre-existing clouds in the atmosphere.
• Drones are charged into the clouds and cause an electric shock due to which they clump together and cause rainfall.
• In this process either silver iodide, potassium iodide or dry ice (solid carbon dioxide) is dumped onto the clouds causing rainfall.
• Cloud-seeding chemicals can be dispersed in clouds in two ways:
  • By Fly-through aircraft or
  • By Ground-based dispersion devices that use rockets or guns to fire canisters into the sky.

Benefits

• It improves a cloud’s ability to produce rain or snow, supplements the rainwater supply.
• It cleans the atmosphere by introducing tiny ice nuclei into certain types of subfreezing clouds.
  • These nuclei provide a base for snowflakes to form.

Dangers

• So far, experts haven’t found any harmful effects of cloud seeding with silver iodide on the environment.
  • But Silver iodide can be toxic to aquatic life.
• The concentration of silver in a storm from cloud seeding is far below the accepted limit of 50 micrograms per litre.

Cloud Seeding in India

• In India, these operations were conducted during the years 1983, 1984–87,1993-94 by Tamil Nadu Govt due to severe drought.
• In the years 2003 and 2004 Karnataka government initiated this technique.

Sources

1. Wikipedia
2. India Today