Delhi’s first cloud seeding experiment (Image Source: SK Chakraborty)
The Delhi government conducted two cloud seeding operations on Tuesday in an attempt to bring artificial rain and reduce the city’s severe pollution levels. These sorties were part of a memorandum of understanding (MoU) signed with IIT Kanpur on September 25, aimed at conducting experimental trials across northwest Delhi. The Directorate General of Civil Aviation (DGCA) granted permission to carry out these operations between October and November.
The goal of this project is to explore cloud seeding as a scientific way to combat pollution during Delhi’s annual smog season. In May 2024, the government approved five cloud seeding trials at a total cost of ₹3.21 crore.
Cloud seeding is a scientific technique that encourages rainfall by releasing substances like silver iodide, sodium chloride, or potassium chloride into the clouds. These particles act as condensation points where water droplets can form, making rain more likely.
Delhi’s Environment Minister Manjinder Singh Sirsa described the project as “a huge step taken by the government to mitigate pollution,” and said that more trials would be held soon.
According to IIT Kanpur’s report, two sorties were flown on Tuesday one from IIT Kanpur and another from Meerut using a Cessna aircraft equipped with flares containing silver iodide and salt.
The first flight took off from Kanpur at 12:13 p.m. and landed in Meerut at 2:30 p.m., dispersing about 3–4 kilograms of seeding chemicals.
The second flight left Meerut at 3:45 p.m. and returned by 4:45 p.m., releasing another 4 kilograms of the mixture.
The aircraft flew over several areas, including Khekra, Burari, North Karol Bagh, Mayur Vihar, Sadakpur, Bhojpur, Noida, and Greater Noida.
Sirsa told India Today that eight flares were used, each weighing 2–2.5 kilograms and burning for about 2 to 2.5 minutes.
Despite the effort, the operation didn’t bring visible rain because the atmosphere lacked enough moisture. For cloud seeding to succeed, humidity must be above 50%, so that the silver iodide or salt can help form raindrops. On Tuesday, humidity was only 10–20%, far below the required level.
Minister Sirsa said, “Generally, we need moisture of over 50%. IIT Kanpur carried out the experiment—we are dependent on them. This trial was done to check if we can do cloud seeding in moisture conditions of 10–15%.”
IIT Kanpur Director Manindra Agrawal told NDTV, “Unfortunately, the clouds that are present today do not have very high moisture content. I am told it was only up to 15–20%. So, the possibility of causing rain with such low moisture content is not very high.”
He added that not all clouds are suitable for seeding, saying, “What our team found was that the cloud cover had very little moisture content… So we do not expect any rain to occur today.”
Agrawal also clarified that the trial was meant to test feasibility under difficult conditions: “It is an SOS solution. When you have a crisis situation, very high pollution, it is one of the methods one can attempt in order to bring down pollution. It is not a permanent solution.”
There was minimal rainfall 0.1 mm in Noida and 0.2 mm in Greater Noida—recorded around 4:00 p.m. according to IIT Kanpur’s official report.
Even though there was little rain, pollution levels slightly improved. Data from monitoring stations showed a small drop in PM2.5 and PM10 levels after the seeding operation:
| Location | PM2.5 Before | PM2.5 After | PM10 Before | PM10 After |
|---|---|---|---|---|
| Mayur Vihar | 221 | 207 | 207 | 177 |
| Karol Bagh | 230 | 206 | 206 | 163 |
| Burari | 229 | 203 | 209 | 177 |
Researchers said the minor improvement may have been due to denser moisture created by the seeding chemicals, which helped pollutants settle even without strong winds.
Both the Delhi government and IIT Kanpur plan to continue trials based on future weather conditions. Minister Sirsa said, “If we have done cloud seeding, then we are going to see cloud-seeding rain only.” He added that the goal was to collect data from various humidity levels to see how effective seeding can be in different conditions.
About 9–10 more trials are planned in northern Delhi and surrounding areas, guided by the India Meteorological Department (IMD) for wind and cloud forecasts.
Delhi’s first cloud seeding experiment may not have brought significant rain, but it has opened a new chapter in the use of weather modification technology for pollution control. Experts agree that while it cannot replace long-term solutions like emission control, cloud seeding could offer temporary relief during severe smog episodes if the weather cooperates.
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