An ambitious effort to combat New Delhi’s hazardous air pollution by inducing artificial rain has failed to produce the desired results, officials confirmed. The cloud seeding experiment, conducted on October 28, 2025, was intended to wash away the toxic smog that regularly chokes the megacity, but unsuitable atmospheric conditions rendered the attempt unsuccessful, leaving pollution levels dangerously high.
The experiment’s failure highlights the immense challenges in deploying technological fixes for deep-rooted environmental problems. Despite meticulous planning by the Indian Institute of Technology, Kanpur (IIT Kanpur), the meteorological conditions over the capital were not conducive for weather modification, as the specific cloud characteristics necessary for generating precipitation were absent. Critics and atmospheric scientists have reiterated that such interventions are, at best, temporary measures that do not address the complex, systemic sources of Delhi’s annual air quality crisis.
Anatomy of the Experiment
The cloud seeding trial was a joint operation between the Delhi government and a team of experts from IIT Kanpur. The plan involved the use of two specially equipped aircraft that took off from airfields in Kanpur and Meerut. These planes flew over several designated areas of the national capital, including Khekra, Burari, North Karol Bagh, and Mayur Vihar, releasing seeding agents into the atmosphere.
The core of the operation involved firing flares containing a salt mixture into existing cloud formations. Each flare weighed approximately 0.5 kilograms, and eight flares were released during each flight. These particles, typically silver iodide or sodium chloride, are designed to act as condensation nuclei, encouraging tiny water droplets or ice crystals within the clouds to coalesce and grow heavy enough to fall as rain. This process has been explored for decades in various parts of the world, primarily for drought mitigation.
Insufficient Moisture Leads to Failure
The fundamental reason for the experiment’s inability to generate rainfall was the lack of adequate moisture in the atmosphere. For cloud seeding to be effective, clouds must contain a sufficient amount of supercooled water vapor. Researchers confirmed that the clouds over Delhi at the time of the trial had only 15–20% moisture content, which is substantially below the minimum 50% threshold considered necessary for a successful seeding operation. While some trace amounts of drizzle were reported in outlying regions like Noida, no measurable rainfall occurred over Delhi itself.
This outcome was predicted by some meteorological analyses. A study by researchers at IIT Delhi, published around the time of the trial, concluded that Delhi’s winter climate is climatologically unsuitable for consistent and effective cloud seeding. Their analysis of a decade’s worth of weather data (2011–2021) revealed that the necessary window of opportunity—characterized by high humidity and dense cloud cover—is rarely open during the peak pollution months of October through February. The study, which has not yet been peer-reviewed, found only 92 viable days for such operations over a 10-year period.
A Silver Lining of Data
Despite the failure to induce rain, project leaders from IIT Kanpur stressed that the effort was not a total loss. Manindra Agrawal, the director of IIT Kanpur, stated that the experiment provided a wealth of valuable data that will inform future research, particularly in understanding the dynamics of pollution. The team had established 15 monitoring stations across the city to measure air quality and atmospheric conditions before, during, and after the seeding flights.
The data collected from these stations indicated a marginal and temporary improvement in air quality. A modest reduction of 6–10% in the concentration of harmful particulate matter—both PM2.5 and PM10—was recorded following the seeding. Professor Agrawal noted that this demonstrated that even with very low moisture levels, seeding can have some impact, providing crucial information for refining future models. He also defended the experiment against criticisms of its cost, estimating that seeding a 300-square-kilometer area costs around Rs 60 lakh, a figure he argued is minor compared to the total expenditure on pollution control in the city.
Scientific Skepticism and Temporary Effects
The Delhi experiment has drawn significant criticism from the broader scientific community, with many experts dismissing cloud seeding as a superficial solution to a chronic problem. Several atmospheric scientists have labeled such efforts as “gimmicks” and “snake-oil solutions” that divert attention and resources from tackling the root causes of air pollution. They argue that even if the experiment had succeeded in creating rain, the relief would have been fleeting.
Research, including the recent IIT Delhi study, shows that while heavy rainfall can effectively wash pollutants from the air, the effect is short-lived. Air quality typically reverts to its previous hazardous levels within one to five days as pollution from unabated sources pours back into the atmosphere. Therefore, experts conclude that cloud seeding cannot be considered a primary or reliable strategy for managing Delhi’s winter air pollution crisis.
The Unyielding Sources of Smog
Delhi’s air pollution is a complex, multi-faceted crisis that intensifies every winter due to a combination of anthropogenic emissions and meteorological phenomena. On the day after the experiment, October 29, 2025, the city’s Air Quality Index (AQI) remained in the “poor” category at 275, with some areas registering over 327. This persistent pollution stems from a convergence of sources.
Key Pollution Contributors
- Vehicular Emissions: Fumes from millions of cars, trucks, and motorcycles are a major year-round contributor to the city’s toxic air.
- Industrial Pollution: Emissions from factories and power plants in and around the Delhi-NCR region add a significant load of pollutants into the atmosphere.
- Agricultural Burning: The seasonal practice of burning crop residue, or stubble, in the neighboring states of Punjab and Haryana sends vast plumes of smoke across the Indo-Gangetic Plain, which can account for over 35% of PM2.5 levels during peak periods.
- Construction Dust: Pervasive construction and road dust contribute heavily to the particulate matter suspended in the air.
- Meteorological Conditions: During winter, low wind speeds and temperature inversions—a phenomenon where a layer of cool air is trapped under a layer of warmer air—prevent pollutants from dispersing, locking them close to the ground.
Medical experts warn that chronic exposure to Delhi’s air is a public health catastrophe, equating it to smoking 10 cigarettes a day and linking it to severe respiratory and cardiovascular diseases.
