Silver flares fired into clouds: Delhi takes two shots at summoning rain, Pg1.

Key Highlights:

• Delhi conducted artificial rain experiments on Tuesday to combat high air pollution levels, with the Air Quality Index at 294 (poor).
• Two cloud-seeding trials were performed at 12:13 pm and 3:45 pm in collaboration with IIT-Kanpur.
• Light rainfall of 0.1-0.2 mm was reported in Noida and Greater Noida following the trials.
• The Delhi government and IIT-Kanpur previously conducted a test run on October 23 covering areas including Kanpur, Mehrauli, and Aligarh.

Detailed Insights:

• The cloud-seeding process involved a Cessna 206H aircraft releasing silver iodide and sodium chloride into clouds from an altitude of 4,000-6,000 feet.
• The India Meteorological Department (IMD) provided a forecast of cloudy skies, creating a window for the cloud-seeding attempts.
• IIT-Kanpur estimates any precipitation would be limited in scale and could begin within 15 minutes to 4 hours of seeding.
• The MoU between IIT-Kanpur and the environment department allocated Rs 3.21 crore for five cloud-seeding trials.
• Experts suggest that while weather systems have enabled moisture influx, cloud-seeding is a complex process and only a short-term solution.
• Environmentalists emphasize the need to address sector-specific emissions from transport, power, and construction for long-term air quality improvement.

Scientific/Technical Concepts Involved:

• Cloud Seeding: A weather modification technique to increase precipitation by dispersing substances into the air that serve as cloud condensation or ice nuclei.
• Silver Iodide: A chemical compound used in cloud seeding as an ice nucleating agent to promote ice crystal formation in clouds.
• Air Quality Index (AQI): An index for reporting daily air quality, indicating how clean or polluted the air is, and associated health effects.