Cloud seeding trials in Delhi sees mixed results, IIT Kanpur director says effort wasn't 'fully successful' as political row erupts

On Tuesday (October 28), a small, single-engine aircraft operated by IIT Kanpur flew over northwest Delhi and parts of the National Capital Region (NCR) to conduct cloud seeding trials. The aircraft released 16 flares—eight during each of the two attempts—containing silver iodide and sodium chloride compounds over areas such as Burari, Mayur Vihar, and Noida. The goal was to trigger rainfall as part of an experimental plan to reduce air pollution, which often worsens during this time of year.

However, the trials did not result in substantial rain, despite the Delhi government’s environment minister, Manjinder Singh Sirsa, calling the operation a ‘success’. According to Sirsa, this initiative is a major step for Delhi, as it explores cloud seeding as a potential method for air pollution management. He emphasised that the purpose was to assess the impact of cloud seeding under real-world conditions in Delhi's unique humidity levels.

The exercise, which has become politically contentious, also saw criticism from AAP leader Saurabh Bharadwaj, who questioned the timing of the trials, suggesting that the India Meteorological Department had already predicted rain on that day. "Will Lord Indra clarify if this is artificial or natural rain?" Bharadwaj said at a press conference. The cloud seeding program was first proposed by the AAP government in the winter of 2023 but faced delays due to unfavorable meteorological conditions. Last winter, the AAP again pushed for the initiative, only to face hurdles in obtaining necessary permissions. Sirsa, on the other hand, has previously accused AAP of talking about such plans without action.

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What IIT Kanpur director say about cloud seeding?

An IIT Kanpur report released on the same day said that ‘trace’ rainfall—0.1mm in Noida and 0.2mm in Greater Noida—was observed, but it also noted that these amounts were too small to be recorded by official weather stations. The report highlighted a reduction in particulate matter (PM2.5) in areas like Mayur Vihar, Karol Bagh, and Burari, where PM2.5 levels dropped after the cloud seeding attempts. This decrease in pollutants was possibly linked to the moisture content in the clouds, which helped to settle some of the particles.

IIT Kanpur’s Director, Manindra Agarwal, offered a more cautious assessment of the trial. He described the results as “not completely successful”, attributing the failure to the low moisture content in the clouds, which was only about 15-20%. “The clouds just didn’t have enough moisture for us to trigger significant rainfall. It’s not a magic fix for pollution, but an emergency measure,” Agarwal was quoted saying to NDTV. Despite this setback, he expressed optimism, saying that the team would attempt another round of seeding the following day, hoping for better results. Agarwal further clarified that the mixture used in the trials consisted of 20% silver iodide and the rest was a combination of common rock salt and sodium chloride.