Delhi to try induced rain to fight bad air
To be sure, there remain widespread doubts among the scientific community over the effectiveness of cloud-seeding
The Delhi government will consider a proposal to carry out cloud seeding — a technique that induces artificial rain over an area — in a bid to tamp down the Capital’s severe pollution crisis, state environment minister Gopal Rai said on Wednesday.
A final decision will depend on receiving approvals and be based on meteorological factors, Rai said as extreme pollution levels cast a noxious haze over the Capital.
Rai’s announcement came after a delegation from the Indian Institute of Technology, Kanpur (IIT-K)and the Confederation of Indian Industry (CII) on Wednesday met him and lieutenant governor VK Saxena and proposed to implement the pilot cloud-seeding project.
To be sure, there remain widespread doubts among the scientific community over the effectiveness of cloud-seeding as a practice to induce rain.
While Rai said that the government could attempt to implement the project around November 20 or November 21, he asked IIT-K to first submit a proposal to the Delhi government, which will be presented to the Supreme Court on Friday.
The LG too has sought a proposal on the same from the delegation.
“A delegation from CII & IIT, Kanpur met today to discuss the possibility of cloud seeding -- artificial rain in the capital, for mitigating the prevalent air pollution. Enquired about the effectiveness of the technology and asked them to submit a concrete proposal,” Saxena said.
CII Delhi president, Puneet Kaura, said that they informed the government and the LG about past experiments on cloud seeding, with the most recent experiment carried out successfully this year.
Cloud seeding is a weather modification technique, where a compound, silver iodide (AqI), is released into the atmosphere to aid the formation of ice crystals and improve the ability of the cloud to create rain. Silver iodide helps in the creation of tiny ice nuclei, which are required to induce rain, in clouds.
Vehicular emissions and smoke emanating from burning farmlands in the neighbouring states have led to increased pollution levels, which have been only exacerbated by lower temperatures and calm winds that have prevented the dispersal for pollutants. Both rain and windy conditions are necessary at present to improve Delhi’s toxic air quality which has been consistently worse and extremely dangerous for the health of its millions of residents.
“In Delhi, due to the prevailing meteorological conditions, there is also a possibility that winds will continue to remain calm and there can be stagnation in the air. We have been enforcing different measures under the Graded Response Action Plan (GRAP) already, but another possibility to bring down pollution — cloud seeding — was also looked at on Wednesday, with the second meeting on this topic, held with IIT Kanpur,” said Rai, stating the the government had earlier held a meeting in this regard on September 12.
According to IIT Kanpur, cloudy conditions are a prerequisite to implement the technique. The India Meteorological Department has forecast such weather conditions on November 20 and 21, Rai said, adding , “which is when we are now trying to do this pilot project”. A proposal has been sought from IIT Kanpur in this regard by Thursday, he added.
“We will then present it in front of the Supreme Court. Since a number of permissions, including the Centre’s, are needed for this, we are hopeful the Supreme Court can help us get permissions on time and assist us in carrying out this experiment,” Rai said.
IIT-Kanpur has experimented with the technique twice in Kanpur, once in 2018 and more recently during this monsoon season, said its professor SN Tripathi.
“Both attempts were made in Kanpur and both produced rain. Adequate cloudiness is required for the same and it can be done using even one aircraft too,” Tripathi said, stating that the institute has its own aircraft on which seeding equipment is attached. “This aircraft has the necessary modification approval, but to attempt this in Delhi, additional permissions will be needed,” he said.
On the cost that would be incurred on the project, CII chief Kaura said that the “technique is fairly cheap to execute.”
Outside India, cloud seeding has most notably been done in China, where different cities have their own cloud-seeding plans. China takes assistance of the military to carry out this exercise. In France too, this is done in coordination with over 20 different departments, largely to prevent hail from falling on agricultural fields in spring and summer months.
Madhavan Rajeevan, former secretary, ministry of earth sciences said cloud seeding can be carried out with a decent amount of success. “I cannot comment on its possibility in Delhi or the impact or air pollution, but cloud seeding has been done to a reasonable amount of success in both 2018 and 2019 by the Indian Institute of Tropical Meteorology in Maharashtra’s Solapur,” he said.