Delhi prepares for first artificial rain in July - Why now, and how it will work

Dark clouds seen in the sky before heavy rains in New Delhi. (Representative image)

In a first for the national capital, Delhi is set to witness artificial rain through cloud seeding, an experimental measure to combat its notoriously hazardous air pollution. If weather conditions allow, the operation will take place in the window between July 4 and 11, with the goal of cleansing the city's atmosphere and offering its residents temporary relief from toxic air, PTI reported.

The initiative, titled ‘Technology Demonstration and Evaluation of Cloud Seeding as an Alternative for Delhi NCR Pollution Mitigation’, is being spearheaded by the Delhi Environment Department in collaboration with the Indian Institute of Technology (IIT) Kanpur.

The Delhi government, under the leadership of Chief Minister Rekha Gupta, has termed this a “historic step” in urban pollution control. PTI quoted Environment Minister Manjinder Singh Sirsa as saying, “Our aim is to give Delhiites clean air. That’s why we’re taking this bold step of artificial rain. We are hopeful it will bring meaningful change.”

Why now?

Delhi’s air quality routinely dips to severe levels, particularly during the winter months, prompting the need for unconventional and emergency interventions. While cloud seeding has been previously discussed, this is the first time the plan is being executed in the capital.

Sirsa noted that conditions are not suitable for seeding until July 3, but a flight window between July 4 and 11 has been proposed. A backup request has also been sent to the Directorate General of Civil Aviation (DGCA) in case weather conditions remain unfavourable.

“This initiative marks a historic step in urban pollution control and is being carried out for the first time by the Environment Department under Chief Minister Rekha Gupta’s leadership,” he told PTI.

What is cloud seeding?

Cloud seeding is a weather modification technique aimed at inducing artificial rainfall. It involves the dispersal of chemicals like silver iodide, iodised salt and rock salt into moisture-laden clouds. These particles serve as condensation nuclei, accelerating droplet formation, which leads to precipitation.

The most effective cloud type for seeding is nimbostratus, typically found at altitudes between 500 and 6,000 metres. According to IIT Kanpur and global studies, the success rate for such operations lies between 60% and 70%, though it is highly dependent on existing atmospheric conditions.

How will it work?

IIT Kanpur has developed a specialised formulation for the seeding operation. As per a TOI report, here's how the experiment will be conducted:

Aircraft: Modified Cessna aircraft will be equipped with flare-based systems to disperse the seeding chemicals.
Flight plan: At least five sorties will be conducted over low-security air zones in northwest and outer Delhi, each lasting around 90 minutes and covering approximately 100 sq km.

Execution team: The operation will be managed by scientists from IIT Kanpur, who had previously tested this technique using a mist-sprinkler system aboard their own aircraft.

The flight plan has been submitted to the India Meteorological Department (IMD) in Pune for technical coordination and necessary clearances are being obtained from aviation authorities.

Politics and controversy

The announcement comes amid political sparring over Delhi’s pollution control efforts. Aam Aadmi Party (AAP) Delhi chief Saurabh Bharadwaj had previously accused the BJP-led central government of obstructing anti-pollution measures and mocking the artificial rain proposal.

PTI cited Sirsa as hitting back, stating: “We were the ones who signed the MoU first, made all the payments to IIT Kanpur and applied for the necessary approvals because we want to take real action.” He added that the current government, under Chief Minister Rekha Gupta, had moved swiftly to implement the plan within four months of taking office.

What happens next?

While the city awaits favourable cloud conditions, preparations are underway for what could be a watershed moment in environmental intervention. Though artificial rain is unlikely to be a permanent fix, the Delhi government is hopeful that it may offer short-term respite and provide critical learnings for future applications.

If successful, the trial could open doors to similar operations in other parts of the country battling air quality emergencies.