The project's chief said on Thursday that Indian scientists plan to seed clouds for the first time to cause heavy rain in select regions of New Delhi, believing that this will be enough to combat the haze that has gripped the world's most polluted capital for a week. Every year, Delhi's air quality suffers as cold air absorbs pollutants from a range of sources, including automobiles, industry, construction dust, and agricultural waste burning.
Scientists anticipate some cloud cover over the city around Nov. 20 and hope it will be large enough - and have a high enough moisture content - to trigger heavy rain via salt seeding, according to Manindra Agrawal, a scientist at the Indian Institute of Technology at Kanpur who is leading the trial.
The initiative, expected to cost 10 million rupees ($120,000) for 100 square kilometers (38.6 square miles), would require spraying a mixture of salts containing silver iodine into clouds, according to Agrawal. "We don't expect that big a cloud that will cover the entire Delhi, but a few hundred kilometers would be good," he told the news agency.
To reduce pollution, the city of 20 million people, stretched over nearly 1,500 square kilometers (579 square miles), has already closed all schools, halted building, and announced car limits. The city's air quality index was 506 early Thursday, which is classified as "hazardous" by Swiss organization IQAir. According to Gufran Beig, the founder director of the federal government's air-quality monitoring agency SAFAR, Delhi requires heavy and broad rain to wash out pollution, and light rain could exacerbate the situation.
The current airflow transports smoke from crop residue burning in Punjab and Haryana to Delhi, which has its pollution sources and currently has nearly no wind. "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 told the news agency.
The Delhi government is attempting to gain approval for the project from the Supreme Court, which is currently examining pollution-related cases. Several countries, including Mexico, the United States, China, Indonesia, and Malaysia, have utilized cloud seeding to produce rain, improve air quality, and irrigate crops during droughts. However, in 2021, a plan to seed clouds over New Mexico's mountains to boost snowfall was scrapped because of concerns that it might poison people and the environment.