Why Cloud Seeding Failed to Bring Rain in Delhi: IIT Kanpur Director Explains -

New Delhi:

Delhi’s eagerly awaited cloud seeding test did not produce rain on Tuesday, with the director of IIT Kanpur, Manindra Agarwal, stating that the operation was “partially successful” due to a lack of moisture in the clouds.

Speaking to NDTV, Agarwal noted that the clouds over Delhi had only about 15 to 20% moisture in them, and so it was hard for the particles placed into the clouds to create rain. “As for rain, we haven’t had any thus far. Unfortunately… the clouds were not creating high moisture. The possibility of causing rain with low moisture is not high if any moisture at all,” explained Agarwal.

How the Concept Worked

The Delhi government had partnered with the Indian Institute of Technology-Kanpur (IIT-K) to execute the trials in a hurry to combat threatening air pollution. The seeding combination used by the research team consisted of 20% silver iodide and other components, which were rock salt and common salt.

On Tuesday, the team activated 14 flares from the plane, which dispersed the mixture into the targeted cloud formations. While the immediate result did not fully meet expectations, Agarwal noted that the experiment increased the team’s confidence moving forward to try under better conditions.

“We have had mixed predictions around rain for today. Some predicted rain; others didn’t. What our team found was that the clouds we went over had very little moisture. So, we do not expect to get sufficient rain today,” he said.

What’s Next for Cloud Seeding in Delhi

There are two more flights for cloud seeding on Wednesday, assuming sufficient cloud cover persists. Agarwal noted that such experiments are contingent on weather and cannot be taken as a method for guaranteed rainfall.

Referring to the operation as an “SOS solution,” Agarwal reiterated that cloud seeding should not be conceived as a long-term solution to Delhi’s pollution.

“It is not a long-term answer. It is an emergency alternative that one can try only if the pollution level is very high. The long-term solution is to control pollution,” Agarwal said.

He added that the operational costs are currently high because the aircraft were coming from Uttar Pradesh, but those costs would potentially decrease for future attempts.

Findings of the Delhi Government

Even without significant rainfall, the Delhi government asserted that the trial did have some demonstrable effect on air quality in the areas where the tests were conducted.

According to the government’s initial report, there was light rainfall recorded — 0.1 mm in Noida and 0.2 mm in Greater Noida around 4 p.m. on Tuesday. More importantly, pollution levels did show a slight decrease after seeding.

The PM level of 2.5 dropped from 221-230 to a low range of 203-207 in monitoring stations in Mayur Vihar, Karol Bagh, and Burari and PM 10 level decreased from 206-209 to a low range of 163-177 in the same areas.

The report stated that changes occurred, however minor, and that it did show some evidence that cloud seeding temporarily diminished particulate matter levels in the atmosphere providing brief respite during periods of significant pollution.

A Move in the Right Direction, not a Solution

Although Tuesday’s experiment did not produce rainfall in the capital, scientists believe it provided important knowledge about how to improve cloud seeding to work more effectively in Indian climates. As Agarwal said, even limited rainfall or humidity would benefit people by reducing pollution temporarily- but the real problem is still dealing with the causes of Delhi’s smog situation. “Any effort that causes less pollution is better for all,” Agarwal said. “Even if it rains a few days later, it is still providing relief.”