How IIT-K ‘success’ report ignores natural patterns

NEW DELHI: An unsigned report from IIT Kanpur, shared by Delhi environment minister Manjinder Singh Sirsa on Tuesday, contends that the cloud seeding experiment in Delhi was somewhat successful, citing rainfall data and air quality improvements at three locations.

- Abhishek Jha

But as HT’s report on the experiment, published on October 29, pointed out, the report cites rain data from Windy.com, awebsite that displays modelled estimates rather than measured rainfall. And the claim of cleaner air suffers from equally serious methodological failures.

What IIT Kanpur claimed

The report stated: “The PM 2.5 was 221, 230, and 229 reported from Mayur Vihar, Carol (Karol) Bagh, and Burari, respectively, before cloud seeding, which got reduced to 207, 206, and 203, respectively, after the first seeding. Similarly, PM 10 was 207, 206, 209, which got reduced to 177, 163, 177 at Mayur Vihar, Carol Bagh, and Burari, respectively. Given that winds were negligible, one possible explanation is that the denser moisture content created due to seeding particles has helped in settling down a portion of these particles, which translated to these reductions.”

Thisis nota scientifically sound way of assessing or reporting air quality improvement. Here is why.

1: No units specified