Cloud Seeding Over Delhi On Hold, IIT Kanpur Flags "Insufficient Moisture"

Cloud seeding trials over Delhi have been put on hold due to insufficient moisture in the clouds. The team from the Indian Institute of Technology (IIT) in Kanpur, which is overseeing cloud seeding to tackle Delhi's air pollution, conducted two rounds of cloud seeding trials yesterday, but no rain followed. "The cloud-seeding activity planned for today has been put on hold due to insufficient moisture in the clouds. The process is highly dependent on the right atmospheric conditions," a statement from IIT Kanpur said.

"While rainfall could not be triggered yesterday because moisture levels were around 15 to 20 per cent, the trial delivered valuable insights. Monitoring stations set up across Delhi captured real-time changes in particulate matter and moisture levels. The data shows a measurable reduction of 6 to 10 per cent in PM2.5 and PM10 concentrations, indicating that even under limited moisture conditions, cloud seeding can contribute to improved air quality," the statement added.

"These observations strengthen our planning for future operations and allow us to better identify conditions where this intervention can deliver maximum benefit. Such learnings form the foundation for more effective deployments ahead. IIT Kanpur remains committed to advancing this research with scientific discipline and a clear focus on improving environmental outcomes for the National Capital Region," the premier institute said.

Delhi environment minister Manjinder Singh Sirsa said seven more trials of cloud seeding are planned. "Two trials were carried out yesterday, but due to low moisture, rain did not take place," he said.

Cloud seeding is a weather modification technique mostly used to cause rainfall in parched areas. This involves spraying tiny particles such as silver iodide or chloride onto clouds using an aircraft. These particles act as nuclei for water droplets or ice crystals, potentially causing precipitation or rain. The results, however, depend on multiple factors such as cloud type, temperature, moisture, and wind.

Earlier, IIT Kanpur director Manindra Agarwal spoke to NDTV after yesterday's trials and said the possibility of causing rain with such low moisture content is not very high. "But this trial has given more confidence to our team that we can continue conducting them," he said.

The senior academic made it clear that cloud seeding could not be a long-term solution to Delhi pollution. "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. The permanent solution, of course, is to control the sources of pollution. Ideally, we should reach a point when there is no need for cloud seeding. But until that happens, this is one tool that is available for reducing pollution to an extent," he said.

Agarwal said the moisture content in clouds was around 15 per cent yesterday and added that this needs to be around 50 per cent for a possibility of rain.