For the first time, Indian scientists plan to seed clouds to trigger heavy rain in some areas of New Delhi. They hope this will be enough to tackle smog gripping the world's most polluted capital, the project's head said on Thursday.
Air quality dips in Delhi before winter every year, when cold air traps pollutants from a variety of sources, including vehicles, industry, construction dust and the burning of agricultural waste.
Scientists expect some cloud cover over the city about November 20 and are hoping this will be large enough — and with high enough moisture content — to trigger heavy rain via seeding with salts, said Manindra Agrawal, a scientist at the Indian Institute of Technology at Kanpur, who is leading the trial.
The project, estimated to cost 10-million rupees (R2.2m) for 100km², involves spraying into clouds a mix of salts that include silver iodine, Agrawal said.
“We don't expect a big cloud that will cover the entire Delhi, but a few hundred kilometres would be good,” he said.
We don't expect a big cloud that will cover the entire Delhi, but a few hundred kilometres would be good
— Manindra Agrawal, scientist
The government of the city of 20-million people, spread over about 1,500km², has already shut schools, stopped construction activities and said it will impose restrictions on vehicle use to control pollution.
The air quality index in the Delhi was 506 early on Thursday, which is categorised as “hazardous” by Swiss group IQAir.
The city needs heavy, widespread rain to wash away pollutants and light rain could worsen the situation, said Gufran Beig, the founder director SAFAR, the federal government's air-quality monitoring agency.
Current airflow is carrying smoke from crop residue burning in the states of Punjab and Haryana to Delhi, which has its own pollution sources and where there is now almost no wind, Beig added.
“So unless a huge pressure is established by intense rain, this chain of transport from Punjab to Delhi will not be broken, and once it is broken, it is difficult for the chain to form again for some time,” he said.
The Delhi government is seeking approval for the project from the supreme court, which is hearing petitions related to pollution.
Several countries have used cloud seeding to produce rain, improve air quality and water crops in times of drought, including Mexico, the US, China, Indonesia and Malaysia.
However, in 2021, a plan to seed clouds over the mountains of New Mexico to increase snowfall was pulled after allegations it could poison people and the environment.
Reuters
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