Cloud seeding is a technique that aims to increase precipitation from clouds
As the air in the national capital has turned 'severe' with the air quality index touching nearly 500 in some areas, the Delhi Government has requested the Centre to allow cloud seeding- a method used to induce artificial rain to combat air pollution. According to experts, artificial rain can wash away pollutants from the atmosphere and help improve the air quality.
Cloud seeding is a weather modification technique that aims to increase precipitation from clouds. Several steps are included in making an artificial rain possible - including identification of clouds suitable for the process and then seeding them with some agents which provides water droplets with a particle to converge around.
How Is Artificial Rain Induced?
First, meteorologists identify clouds that are suitable for seeding. These clouds must have sufficient moisture but lack the necessary conditions to produce significant precipitation on their own.
Then, some commonly agents are used to seed these clouds such as - silver iodide, dry ice, or potassium iodide. Silver iodide is one of the most commonly used agents used for cloud seeding because its structure mimics ice. The dry ice cools the surrounding air when it sublimates, leading to the formation of ice crystals. In some cases, potassium iodide can also be used to seed clouds.
Planes equipped with burners or dispensers then fly through or above the identified cloud layer to release the seeding agent. Once released, the seeding agent acts as a nucleus around which water droplets can form or ice can crystallize. As more ice crystallizes or larger water droplets form, they grow by colliding with other droplets in the cloud. When they become heavy enough, they fall from the cloud as rain or snow, depending on the temperature.
Will Artificial Rain Work For Delhi?
However, the question whether artificial rain would help in improving Delhi's air quality still looms large. According to the Dean of Kotak School of Sustainability in IIT Kanpur SN Tripathi, combating air pollution with artificial rain in the national capital region will not be an easy process.
In conversation with NDTV, he said, "When you already are in such a critical situation with such episodic pollution, artificial rain cannot be experimented or tried now...doing it at this point of time won't help much. It requires a lot of experimentation".
"It is going to be very difficult, given all the clearances it requires and the optimal weather conditions, the probability of it working is very low," he added.