Delhi’s first cloud-seeding trial begins, but no rain yet: What exactly is cloud seeding - Explained

Delhi’s first cloud-seeding trial has officially begun, with aircraft from Kanpur conducting operations over the city’s northern and central zones.

Officials confirmed that the first artificial rain experiment was carried out over Burari and Karol Bagh on Tuesday, marking a milestone in the capital’s fight against its persistent winter smog. The initiative is part of the Delhi government’s broader pollution-control strategy, aimed at improving air quality through artificial rainfall during the high-pollution season.

The designated aircraft, which took off from Kanpur, carried out the operation by dispersing silver iodide and sodium chloride particles into the atmosphere. These compounds help accelerate the condensation process inside moisture-laden clouds, leading to precipitation.

However, officials said rainfall could not be induced due to low atmospheric moisture levels, below 20%, whereas cloud seeding typically requires around 50% humidity to be effective.

Last week, authorities conducted a test flight over Burari, releasing small quantities of the same chemical compounds to assess atmospheric readiness.

“A first-of-its-kind experiment for Delhi”

Delhi Minister Manjinder Singh Sirsa confirmed that the aircraft had taken off for the national capital earlier in the day. Chief Minister Rekha Gupta had previously called cloud seeding “a necessity for Delhi” and “a pioneering step toward addressing the city’s persistent environmental challenges.”

“Cloud seeding is a necessity for Delhi and is the first experiment of its kind. We want to try it in Delhi to see if it can help us control this very serious environmental problem,” Gupta told ANI.

She added, “The blessings of the people of Delhi are with the government, and we feel that this will be a successful experiment and in the future, we will be able to overcome these environmental problems.”

Explained: What is cloud seeding and how does it work?

Cloud seeding is a scientific weather modification technique used to induce rainfall artificially. It works by dispersing fine particles, most commonly silver iodide or salt compounds into existing clouds that already have moisture.

These particles serve as “seeds,” encouraging water droplets in the cloud to merge and grow larger, eventually becoming heavy enough to fall as rain.

There are three main techniques used worldwide:

• Aircraft-based seeding, where chemicals are released mid-air (as in Delhi’s experiment).

• Ground-based generators, which release particles that rise into clouds.

• Rocket or drone systems, which inject seeding materials directly into cloud layers.

While it doesn’t create rain from scratch, cloud seeding can enhance precipitation and temporarily clear dust and pollutants from the air, offering short-term relief in cities grappling with severe air quality issues.

A high-stakes experiment for a choking capital

This marks Delhi’s first operational attempt at artificial rain after years of discussion. While Tuesday’s conditions didn’t yield precipitation, officials said further trials will depend on favourable humidity and wind patterns later this week.

If successful, the experiment could pave the way for larger-scale weather interventions across pollution-affected regions in northern India.

Pollution levels remain ‘very poor’

However, despite the trial, Delhi’s air quality remains severely compromised. The Air Quality Index (AQI) stood at 304 as of 1 p.m. on Tuesday, according to the Central Pollution Control Board (CPCB), falling in the “very poor” category.

Key areas such as Siri Fort (347), Bawana (334), RK Puram (316), Dwarka Sector 8 (311), and Anand Vihar (311) continue to record dangerous pollution levels. The Graded Response Action Plan (GRAP) Stage 2 remains in force across the National Capital Region