Context:
• Delhi’s recent cloud-seeding experiment produced minimal rainfall, raising questions about the effectiveness, sustainability, and environmental risks of using such technology for reducing pollution.
Key Highlights:
- Limited Rainfall Achieved
- IIT-Kanpur conducted cloud-seeding flights dispersing silver iodide and salt particles.
- Rainfall recorded: 0.1 mm in Noida, 0.2 mm in Greater Noida, and no rainfall in Delhi.
- Uncertain Effectiveness in Local Conditions
- Experts warn that convective, low-level clouds common in the plains may not respond well to cloud seeding.
- Any potential improvement in air quality would be short-lived.
- High Costs & Low Returns
- Cloud-seeding projects can cost ₹3.2 crore or more, raising concerns over cost-benefit justification.
Significance
- Cloud-seeding success is highly dependent on cloud characteristics—height, moisture content, type, and the precise timing of particle release. These conditions are often suboptimal in northern plains.
• Air quality experts reiterate that cloud seeding does not address the root causes of Delhi’s pollution, which stem from transport emissions, construction dust, biomass burning, and power sector pollutants.
• For cloud seeding to work, the timing must be early in a cloud’s life cycle—seeding too late causes particles to be washed out by natural rain.
• Delhi’s complex aerosol mix—including sulphates, silica dust, and other particulates—interferes with cloud microphysics, making rain formation harder.
• Cloud formation after seeding may take several hours, with no guarantee of precipitation.
• Environmental concerns persist: silver iodide, although used in small quantities, may pose toxicity risks to aquatic life, and long-term ecological studies remain limited.