Copyright news18
Indian Institute of Technology (IIT)-Kanpur on Wednesday called off its cloud seeding sorties over Delhi after finding poor moisture content in the clouds, which scientists said was not adequate to trigger artificial rain in the region. This marked the second attempt within 24 hours to induce artificial rainfall as part of the capital’s ambitious experiment to combat air pollution. The operation, carried out in coordination with the Delhi government, was aimed at exploring whether artificial rain could serve as an emergency tool to curb the city’s toxic smog levels during peak pollution days. However, despite back-to-back sorties on Tuesday and Wednesday, the attempts failed to bring the desired results. Confirming the development, Professor Soumya Ranjan Sahoo, the scientist authorised by IIT Kanpur to brief the media, told News18, “The sorties have been put on hold since there was poor moisture content in the clouds, which is essential for artificial rains.” Low Humidity Derails Second Attempt According to the research team, the moisture levels in the targeted clouds were less than 20 per cent, whereas successful cloud seeding requires at least 50 per cent humidity for the seeding agents to effectively stimulate condensation and precipitation. “What we found was that the moisture content was too less to trigger rains,” said Professor Manindra Agrawal, Director of IIT Kanpur and principal investigator of the artificial rain project. Professor Agarwal said, “Though we did not achieve success from that perspective, we gathered a lot of useful information. We had set up 15 stations across Delhi to measure pollution levels, and our data shows a slight reduction in PM 2.5 and PM 10 concentrations. This indicates that even a small amount of moisture in the cloud had some impact on air pollution.” He added that the data collected would be instrumental in planning future seeding experiments under more favourable weather conditions. “This is a scientific process — every attempt teaches us something new,” he said. Why Didn’t the Clouds Respond? The failure of the experiment, scientists said, stemmed primarily from the extremely dry atmospheric conditions. During the sorties, humidity levels hovered between 10 per cent and 20 per cent, according to IIT Kanpur and Delhi government officials — far below what is required for the seeding flares to take effect. Cloud seeding involves dispersing particles such as silver iodide or salt-based compounds into the clouds to encourage condensation and rainfall. But when the clouds lack sufficient moisture, the seeding agents have nothing to bind with, rendering the process ineffective. Explaining the challenge, Professor Agarwal, told News18, “Unfortunately, the clouds that are present today do not have very high moisture content. I am told it was only up to 15–20 per cenr. So, the possibility of causing rain with such low moisture content is not very high.” Agrawal said that while cloud cover was visible over parts of the NCR, not all clouds are equally suited for seeding. “What our team found was that the cloud cover had very little moisture content. And this could be true about the part we flew over. So, we do not expect any rain to occur today,” he said. A Costly Failure or a Valuable Experiment? The unsuccessful attempt prompted some political criticism from opposition leaders, who questioned the expenses incurred on the operation and labelled it a waste of public money. However, the IIT Kanpur scientists defended the project, calling it a scientific necessity and an experiment in progress. “As it was an experiment, it implies that it can be successful, and it may also not be successful. If we fear failure and not undertake the experiment, we will not make any progress,” he said, adding that the funds spent were minimal compared to the crores of rupees spent annually to control Delhi’s pollution. Cloud Seeding, a part of MoU The cloud seeding operations form part of a Memorandum of Understanding (MoU) signed between IIT Kanpur and the Delhi government on September 25. The agreement permits a series of experimental trials in northwest Delhi, with special approval from the Directorate General of Civil Aviation (DGCA) to conduct the operations between October and November. The initiative aims to scientifically assess whether artificial rain can be used as a short-term pollution mitigation strategy during Delhi’s high-smog months. The Delhi government had, earlier on May 7, approved a proposal for five cloud seeding trials at a total cost of Rs 3.21 crore. Despite the initial setbacks, IIT Kanpur remains optimistic. The team plans to resume sorties when atmospheric conditions improve, particularly when the humidity levels rise to the threshold needed for effective seeding. “This is a learning process. If all parameters align and adequate moisture is available, we will be ready to fly again. The ultimate goal is to develop a reliable system that can be deployed during severe pollution episodes,” he added.
