Every winter, Delhi transforms into a city shrouded in haze. The Air Quality Index (AQI) rockets into the “severe” zone, schools shutter their doors, and the skyline morphs into a ghostly outline. After Diwali in 2025, the situation turned especially dire, with pollution levels soaring and the city’s residents struggling to breathe. Amid this recurring crisis, the Delhi government has turned to a dramatic—and controversial—solution: artificial rain, or cloud seeding, in the hope of washing away the toxic air.
Cloud seeding isn’t a new idea. The science dates back nearly a century, when European researchers in 1931 experimented with dry ice to trigger rainfall. The big breakthrough came in the 1940s, when scientists Schaefer and Vonnegut at General Electric discovered that silver iodide could serve as an effective ice nucleant, revolutionizing weather modification. Since then, countries like China, the UAE, Indonesia, Malaysia, and most recently Pakistan have used cloud seeding to boost agriculture, control pollution, and even clear skies for major events. In December 2023, Lahore, Pakistan, saw its first artificial rain mission—AQI levels dropped from 300 to 189, though the respite was short-lived, with pollution rebounding within two days, according to ETV Bharat.
So, how does cloud seeding actually work? The process involves dispersing particles—typically silver iodide, chloride, or rock salt—into clouds using aircraft, rockets, or ground-based flares. These particles act as seeds, attracting water vapor that condenses and forms droplets. Under the right conditions, these droplets merge and fall as rain. There are two main types: hygroscopic seeding, which accelerates droplet formation in liquid clouds, and glaciogenic seeding, which uses ice nuclei to trigger precipitation in supercooled clouds. The whole process can take as little as thirty minutes to produce results, but there’s a catch: you need the right kind of clouds, with enough moisture and the right altitude.
Delhi’s pollution woes are a toxic cocktail. Vehicular and industrial emissions, construction dust, biomass and waste burning, and stubble smoke drifting from neighboring states all contribute to the city’s choking air. During the winter, stagnant air traps these pollutants close to the ground, making the situation even worse. As The Times of India notes, the logic behind artificial rain is straightforward—if nature won’t clean the air, perhaps science can lend a hand.
But the reality is far more complicated. Delhi’s winter skies are usually dry, and when clouds do appear—often as part of western disturbances—they’re frequently too high or too short-lived for effective seeding. As Environment Minister Manjinder Singh Sirsa put it, “Cloud seeding only happens when there are clouds. It is scientifically impossible without the clouds.” As of October 2025, there simply weren’t any clouds to work with, stalling the government’s plans.
The pilot cloud seeding project, greenlit by the India Meteorological Department (IMD) in mid-June 2025, is being spearheaded by the Indian Institute of Technology (IIT) Kanpur. Their team will use a special mixture of silver iodide, iodine salt, and rock salt, dispersed via flares from a VT Cessna aircraft. Five flights are planned, each lasting 1 to 1.5 hours and covering at least 100 square kilometers, steering clear of high-security zones like Rashtrapati Bhavan and Parliament House. The target? Nimbostratus clouds between 500 and 6,000 meters in altitude, with at least 50% humidity. The total cost for this ambitious experiment is estimated at Rs 3.21 crore, funded by the Delhi government.
But cloud seeding is no silver bullet. Experts from the IMD, the Commission for Air Quality Management (CAQM), and the Central Pollution Control Board (CPCB) have raised concerns about both its effectiveness and its potential side effects. As one environmental scientist told The Times of India, “You can’t seed what isn’t there—and Delhi’s problem is often a lack of the right clouds.” Even when conditions are ideal, studies suggest a success rate of only 60–70%. And if rain does fall, it may evaporate before it ever reaches the ground, offering little relief to those suffering below.
There are other challenges, too. The process is expensive, involving specialized aircraft, costly chemicals, and advanced technical equipment. Permissions are needed from no fewer than 11 authorities, including the Ministry of Defence, the Directorate General of Civil Aviation, the Ministry of Home Affairs, and several others, as outlined in an IIT Kanpur presentation. Political wrangling has also played a role: previous attempts to launch artificial rain initiatives were derailed by conflicts between the central government and the Delhi administration. Former Environment Minister Gopal Rai accused the Union Environment Minister of stonewalling efforts, claiming that his requests for meetings went unanswered, according to ETV Bharat.
What about the risks? Dr. Anil Gupta, a member of the CPCB, warns that while artificial rain can temporarily reduce toxic elements like particulate matter, sulfur oxide, nitrogen oxide, and benzene, the chemicals used in cloud seeding may have long-term environmental and health impacts. “Artificial rain causes toxic elements like particulate matter, sulphur oxide, nitrogen oxide and benzene to settle to the ground leading to a temporary reduction in the pollution levels,” Gupta explained. But over time, these chemicals can seep into the soil, water, and aquatic life, potentially causing respiratory problems and other health hazards. There’s also the risk of disrupting natural weather cycles, which could lead to unexpected droughts or floods in surrounding regions, affecting agriculture and ecosystems.
Despite these concerns, the Delhi government remains determined. Sirsa described the pilot project as “not just about bringing rain, but a symbol of scientific courage and environmental friendliness.” He emphasized that the government is also deploying anti-smog guns, sprinklers, and strict dust control regulations at construction sites. Still, experts caution that cloud seeding is, at best, a temporary fix. The real solution, they say, lies in tackling the root causes: reducing emissions, enforcing stricter pollution controls, and cracking down on stubble burning.
Globally, cloud seeding has shown mixed results. In China and the UAE, the technique is used regularly, but its effectiveness varies and the long-term impacts remain under study. In India, cloud seeding has yet to be implemented on a large scale, though the IIT Kanpur project could set a precedent for other polluted cities if it proves successful. But as Indian meteorologist Naresh pointed out, “research is still on to fully understand the long term adverse effects of artificial rain.”
For now, Delhi’s experiment with artificial rain remains a story of hope mingled with uncertainty. The idea of “rain on demand” is captivating, but the science—and the sky—may not always cooperate. As the city waits for clouds to gather, the search for cleaner air continues, reminding everyone that sometimes, the solutions to our biggest problems are as elusive as rain in a Delhi winter.
