Indian scientists plan to seed clouds for the first time to trigger heavy rain in some areas of New Delhi, hoping this will be enough to tackle the smog gripping the world’s most polluted capital for a week, the project’s head said on Thursday.
Air quality dips in Delhi ahead of winter every year, when cold air traps pollutants from a variety of sources including vehicles, industries, construction dust, and agricultural waste burning.
Scientists expect some cloud cover over the city around Nov. 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 ($120,000) for 100 square kilometres (38.6 square miles), would involve spraying into clouds a mix of salts that include silver iodine, Agrawal said.
“We don’t expect that big a cloud that will cover entire Delhi, but a few hundred kilometres would be good,”.
The local government of the city of 20 million people, spread over roughly 1,500 square kilometres (579 square miles), has already shut all schools, stopped construction activities, and said it will impose restrictions on vehicle use to control pollution.
The air quality index in the city was 506 early on Thursday, which is categorised as “hazardous” by Swiss group IQAir.
