ENGINEERING THESKIES

Delhi’s skies, thick with haze and desperation, witnessed a remarkable scientific experiment this week — the city’s first-ever cloud-seeding trial.

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It was not just an exercise in weather modification but a reflection of India’s growing urgency to fight the twin challenges of air pollution and water scarcity. The idea that humans can coax the heavens to rain is not new, but its application in the Indian context raises profound questions about science, sustainability, and policy priorities.

Cloud seeding, at its core, is an attempt to enhance natural precipitation by providing “seeds” around which water vapour condenses. ‘These seeds are usually fine particles such as silver iodide, sodium chloride, or potassium chloride, dispersed into clouds using aircraft. When successful, the process can trigger condensation, accelerate droplet fusion, and result in increased rainfall. In cold clouds, silver iodide particles mimic ice nuclei, enabling moisture to accumulate and fall as rain or snow once temperatures rise near the surface. In warm clouds, the process relies on common salts that help water droplets coalesce more efficiently.