Recently cloud seeding was done by IIT Kanpur researchers over the Indian capital to produce artificial rain so as to reduce annual airborne pollution in the autumn and winter months. It failed miserably and did not produce any rain. Besides, the experiment cost about Rs. 3 to 4 crores.

Similarly, efforts of cloud seeding all over the world have hardly produced any rain on demand and yet it is done regularly because politicians get major mileage by announcing it and substantial money for cloud seeding is distributed among their cronies.  It is a win-win situation for both politicians and their cronies.

Genesis of cloud seeding

Cloud seeding was pioneered in the US in the early 1940s to produce snow and rain for recreation and farming. On 13th November 1946, Vincent Shaefer, a researcher at General Electric Ltd. (GE), who is also known as the father of cloud seeding, did the first experiment of cloud seeding in the northern part of New York state when he flew a small plane into a thick cloud cover and sprayed dry ice in it to seed the clouds. Rainfall after a couple of hours was reported based on this experiment. However, experiments done later on were inconclusive and subsequently GE stopped these experiments.   

Reduces Pollution Momentarily

I had the good fortune and honor of knowing Vincent Shaefer who was a research associate of Irving Langmuir in GE. I was working for my Ph.D. in the University of Florida in the 1970s on desalination of sea water and became interested in finding out how evaporating water gets electrically charged. In that context I corresponded with him.

One of the things that Shaefer told me then was that cloud seeding was very dicey and even today, after 80 years, it is unpredictable and data from all over the world has shown that the rainfall produced from cloud seeding is statistically insignificant. Thus, I feel all such attempts at cloud seeding are nothing but mechanisms of politicians helping their cronies with funds.

Cloud seeding has always been done for producing rain for farming. Use of rain to ease air pollution is a recent phenomenon and it is assumed that fine polluting particles in the range of PM 2.5 to 10 may be washed away. However, the particulates in the rainwater again get airborne later on because of rain-based mud formation and splashing.  Besides, it reduces air pollution momentarily. So, cloud seeding will have to be done on a daily basis with lots of money involved.          

Waste Of Taxpayers' Money

Shaefer in 1946 discovered that supercooled water vapor at – 400C, if seeded by suitable agents like dry ice, could produce ice crystals which fall as rain. Thus, cloud seeding requires a good mass of clouds with enough moisture and super cooled to – 400C.  Later on, research showed that better cloud seeding could be done by silver iodide crystals sprayed by small aircrafts. The crystals act as nucleation agents and start the process of rain formation. 

However, there are lots of unknowns in the cloud physics and rain formation process even today. They are:

What gives electric charge to the clouds? Or how does the evaporating water from the sea get electrically charged? How this charge in the cloud produces thunder and lightning. This is basically a discharging mechanism and how does it help in the rain making?How does the seeding material interfere with the lightning or in other words in rain production.

What effect does artificial rain have on the wind direction and velocity of clouds so that the effectiveness of where and when it will rain can be predicted? And how much cloud cover is enough to facilitate the cloud seeding process, i.e. how much moisture is there in the cloud for cloud seeding to succeed? How does industrial and vehicular pollution affect cloud formation and seeding process?    

These unknowns make cloud seeding very dicey and unpredictable and to my mind presently it is a waste of taxpayers’ money.

Plant More Trees

A more workable solution to reduce air pollution is to reduce it at source. This can be done by identifying the air polluting sources and shutting them off or reducing their potential to pollute. For example, make necessary laws to reduce the use of diesel vehicles in the city and replace them by electric-powered mass transport systems like Metro rail or buses as vehicular pollution remains one of the primary causes. Also stopping or reducing polluting industries in the city will further help in the reduction of air pollution.

The most important thing to do in cities like Delhi is to plant more trees. There should be a nationwide campaign to plant trees. Each One Plant One could be a good slogan for such a campaign. A green and healthy city normally has an average of > 35% area of city covered by trees and forest. Indian cities have < 10-15% tree cover. This single act of planting more trees in cities can reduce air pollution substantially.

An even better solution for reducing air pollution in cities like Delhi would be to live in a sustainable manner so that such half-baked ideas as cloud seeding are not needed.

(The writer, an IIT and US-educated Indian spiritual engineer and rural development pioneer,  a 2022 Padma Shri award winner, is the Director, Nimbkar Agricultural Research Institute, Phaltan, Maharashtra.  He can be reached at anilrajvanshi50@gmail.com/@anilraj24.bsky.social)