Each Cloud Seeding Sortie Costs 60 Lakh. Expert Explains How It Will Reduce

Cloud seeding over Delhi for an entire winter would cost approximately Rs 25 crore, and this sum is a small portion of the budget to tackle the air pollution in the national capital, IIT Kanpur director Manindra Agrawal has told NDTV.

The senior academic was speaking a day after an expert team from IIT Kanpur oversaw two sorties of cloud seeding in Delhi. These trips, however, did not lead to rain.

The IIT Kanpur director said that cloud seeding did not cause rain yesterday due to low moisture content in the clouds over the national capital. The moisture content yesterday was around 15 per cent, and it must be around 50 per cent for cloud seeding to be successful.

Highlighting the takeaway from yesterday's exercise, Agrawal said the IIT team had installed measurement equipment at 15 locations in the national capital, and they recorded a 6 to 10 per cent decrease in PM 2.5 and PM 10 pollutants.

What Is Cloud Seeding

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. Aircraft or drones can be used to carry out cloud seeding. Once sprayed or injected into clouds, these particles act as nuclei for water droplets or ice crystals, causing precipitation or rain. The results, however, depend on multiple factors such as cloud type, temperature, moisture, and wind.

Agrawal said a very finely ground mixture is used for cloud seeding. "In this mixture, there are particles of common salt, rock salt, and silver iodide. We inject it into the clouds. So every small particle of it begins to condense water all around it. And when the condensation occurs in excess, it falls like a drop. And when a lot of drops fall, rain happens," the scientist said.

The Cost Factor

Asked about the cost factor, the IIT Kanpur director said a key reason for the high expenses incurred in the exercise yesterday is that the flight took off from Kanpur. "If we regularly do this seeding, we will do it from an airport near Delhi, which will reduce the flight cost," he said.

Agrawal said that yesterday's exercise was conducted across an area of 300 square kilometres. "And the cost of this will be around Rs 60 lakh [this refers to each sortie]. I do not have a detailed calculation, but I have an estimate. This means that Rs 20,000 per square kilometre... if we do it across 1,000 square kilometres, it comes to Rs 2 crore," he said.

The IIT Kanpur director said that by this estimate, if cloud seeding is carried out 12 times during the four winter months -- once in every 10 days -- it would cost around Rs 25 crore. "If we look at the pollution (control) budget of Delhi, this is a very small part of it. I do not think that cost is a big issue."

In May, the Delhi cabinet had approved a budget of Rs 3.2 crore for five cloud-seeding trials -- about Rs 64 lakh per trial. In her first budget presented in March, Delhi Chief Minister Rekha Gupta earmarked a sum of Rs 300 crore for pollution control and emergency measures to "effectively implement environmental reforms".   

'Not A Permanent Solution'

Agrawal made it clear that cloud seeding cannot be seen as a long-term solution for air pollution in Delhi, but only a stopgap measure.

"This is not a permanent solution. In fact, I would say that this is not an ideal solution. The ideal solution is that we control the sources of pollution... When there is no pollution, there is no need for cloud seeding. But it will take time," he said.

"So until the sources of pollution are under control, pollution will continue, and when the amount of pollution increases, people will start suffering from it; cloud seeding is available," Agrawal said.

Delhi's air pollution levels have gone up over the past couple of weeks, and the restrictions under the first and second stages of the Graded Response Action Plan (GRAP) have kicked in.