Cloud seeding a process of injecting chemical substances into clouds to induce artificial rain is gaining traction in India as a potential solution for droughts, pollution, and water scarcity. Cities like Delhi have recently turned to this weather-modification technique to improve air quality during severe pollution spells.
What is cloud seeding?
Cloud seeding involves introducing small particles, known as seeding agents, into the atmosphere. These particles act as nuclei for water vapor to condense around, forming droplets or ice crystals that can trigger rainfall. It’s used to accelerate precipitation, reduce pollution, and enhance water availability.
In India cloud seeding is increasingly seen as a way to combat air pollution and fog, especially in Delhi winter months. Artificial rain can help settle airborne pollutants and dust, temporarily cleaning the air. The Delhi government is actively testing this method in 2025 as part of its pollution-control strategy.
Cost and scope of cloud seeding
The cost of cloud seeding projects varies widely depending on location, method, and scale.
Small-scale projects: ₹12.5 lakh to ₹41 lakh per project
Large-scale projects: ₹8 crore to ₹12 crore per year
The Delhi government’s 2025 trial allocated ₹3.21 crore for five seeding trials. Each trial costs between ₹55 lakh and ₹1.5 crore, with an additional ₹66 lakh for setup and infrastructure. The project aims to provide temporary air-quality relief for about 5–6 days across 100 sq km, costing roughly ₹1 lakh per square kilometer.
Techniques and chemicals used
Two main cloud seeding techniques are used globally.
- Static seeding (for cold clouds): Introduces agents like silver iodide to promote ice crystal formation.
- Hygroscopic seeding (for warm clouds): Uses salt-based agents such as sodium chloride to form water droplets.
In India these chemicals are typically dispersed through aircraft, rockets, or ground machines. The Delhi trials involve 90-minute aircraft flights releasing substances like silver iodide and sodium chloride.
Common chemicals used include silver iodide (AgI), potassium iodide, sodium chloride (common salt), calcium chloride, dry ice (solid CO₂), and liquid propane.
Past Indian projects, such as CAIPEEX, used calcium chloride and magnesium-based flares. The success rate of cloud seeding generally ranges between 10% and 30%.
Benefits of cloud seeding
Cloud seeding provides several potential advantages. It offers drought relief by delivering rain in dry regions, helps wash out pollutants to improve air quality, and supports hydropower generation by replenishing reservoirs. Economically, it can reduce losses in agriculture and healthcare caused by drought and pollution.
Risks and precautions
While considered safe under regulated use, cloud seeding does carry some environmental and health risks. High chemical concentrations could harm aquatic life or soil quality, and silver iodide may cause allergies if inhaled in large amounts. Controlled release, chemical monitoring, and environmental impact assessments are essential to ensure safety.
Experts emphasize that while cloud seeding is not a guaranteed solution, it offers a promising short-term tool to combat pollution and water scarcity. Institutions like IIT Kanpur oversee these trials to ensure safety and effectiveness.
What you can do during pollution spikes
While Delhi experiments with artificial rain citizens can take precautions to reduce health risks. Stay indoors during high-smog days, especially early mornings and late nights. Wear N95 or N99 masks outdoors. Use air purifiers at home or workplaces. Keep windows closed and plants indoors to improve air quality. Stay hydrated and include vitamin-rich foods to strengthen immunity.
Cloud seeding might offer a temporary reprieve from pollution but long-term solutions still lie in reducing emissions, promoting cleaner transport, and restoring green cover across cities.