Planes, Promises, and 0.3 mm of Rain: Delhi’s Costly Experiment

On October 28, 2025, a Cessna 206H aircraft took off from the IIT Kanpur airstrip, carrying silver iodide flares for Delhi’s first cloud seeding experiment in over five decades. The goal was simple: trigger artificial rainfall to ease the capital’s worsening air pollution.

By evening, the results were modest. Rain gauges in Noida recorded just 0.3 millimeters of precipitation. The skies over Delhi remained largely unchanged, and the Air Quality Index stayed in the “very poor” range.

Officials and scientists agreed on the core reason: the atmosphere simply didn’t cooperate. Moisture levels in the clouds were around 15–20%, far below the 50–60% typically needed for cloud seeding to work.

A High-Stakes Attempt to Tame Delhi’s Air

The experiment marked Delhi’s most ambitious weather modification effort since the 1970s. The newly elected Delhi government, working with IIT Kanpur, planned five sorties between October and December to assess whether cloud seeding could be a viable short-term measure for pollution control.

The timing reflected urgency. With Diwali over and stubble burning intensifying in neighboring states, air quality in Delhi was declining rapidly. The government’s objective was to explore any tool that might temporarily ease pollution during peak smog season.

On Tuesday, two flights were conducted from Kanpur toward the National Capital Region. Both released flares over northern Delhi, but meteorological data later confirmed that the target clouds lacked sufficient moisture for effective condensation.

Why It Didn’t Work: Limits of Atmosphere, Not Effort

Experts had warned of the challenge. Cloud seeding typically succeeds only under specific conditions—when cloud systems are thick, humid, and already close to forming rain. Late October in Delhi, however, is marked by dry air and limited convection.

IIT Kanpur Director Manindra Agrawal later explained that the trials were conducted as part of a “learning exercise,” emphasizing that more data would help plan future interventions when humidity is higher.

Meteorologists from the India Meteorological Department echoed that view. “The weather conditions were not ideal,” one official said. “But even unsuccessful trials contribute valuable operational insights.”

The People Behind the Effort

Rekha Gupta, Delhi’s Chief Minister, approved the program as part of a wider initiative to address winter air pollution. Her administration described the project as a “pilot” intended to assess feasibility rather than guarantee outcomes.

Manjinder Singh Sirsa, Delhi’s Environment Minister, oversaw coordination between government agencies and IIT Kanpur. Following the trials, he acknowledged the low rainfall but maintained that the exercise “provided valuable operational experience.”

Manindra Agrawal, IIT Kanpur’s director, led the scientific component. Under his guidance, the institute handled flight planning, flare deployment, and data collection, in collaboration with the Indian Institute of Tropical Meteorology and IMD.

What Happens Next

Two additional sorties remain scheduled through December, depending on weather conditions. Officials have stated that future attempts will only proceed when moisture levels are sufficient.

Experts say cloud seeding is unlikely to be a regular pollution-control method in Delhi’s winter months, given the region’s dry atmospheric profile. However, it could remain a supplementary measure during monsoon or pre-monsoon periods.

Environmental analysts suggest focusing parallel efforts on emission reduction, cleaner transport, and industrial regulation, which offer longer-term gains even if they lack the immediacy of visible interventions like cloud seeding.

The Broader Context

Cloud seeding has shown mixed success worldwide. The United Arab Emirates, China, and parts of the U.S. use it to enhance rainfall, but its results depend heavily on pre-existing weather systems. India has previously tested similar programs in Maharashtra, Karnataka, and Tamil Nadu, with variable outcomes.

Delhi’s experiment fits within this global pattern—an example of a government exploring scientific solutions to environmental crises, even if outcomes remain uncertain.

The BigStory Reframe:

The surface takeaway is straightforward: Delhi’s cloud seeding failed because the skies lacked moisture.

But the deeper story isn’t about meteorology — it’s about how policy, science, and public expectation intersect when cities demand quick fixes for complex problems.

Delhi’s experiment sits at the crossroads of two realities:

• The scientific one, where weather modification remains uncertain and conditional.
• The political one, where environmental crises create intense pressure to act visibly, even if results take time.

In that sense, cloud seeding became a reflection of our broader approach to environmental management — a willingness to explore ambitious solutions even when success is improbable.

This doesn’t make the effort futile. It reveals something valuable: that India’s governance is entering a new phase where scientific tools are being tested not just for outcomes, but for preparedness and institutional learning.

Every failed experiment, if studied honestly, brings a city closer to what might eventually work.

The Takeaway

Cloud seeding in Delhi was never guaranteed to succeed, but it represented a rare collaboration between scientists and policymakers trying to innovate against one of India’s toughest urban challenges.

The effort underscored an important lesson: science cannot always bend to urgency, but even failed experiments can clarify what is—and isn’t—possible in the fight for cleaner air.

FAQs:

1. What is cloud seeding?

Cloud seeding is a weather modification technique that introduces particles such as silver iodide or sodium chloride into clouds to encourage rainfall. These particles act as nuclei around which water vapor condenses, potentially triggering precipitation if enough moisture is already present.

2. Why did the cloud seeding in Delhi fail?

Experts found that Delhi’s clouds on October 28 had very low moisture content — around 15–20%. Effective cloud seeding typically requires humidity levels above 50–60%. In dry air, the introduced particles don’t attract enough water vapor to form raindrops.

3. Who conducted the experiment?

The project was a joint initiative between the Delhi government and IIT Kanpur, in coordination with the India Meteorological Department. The trials used a Cessna 206H aircraft equipped with silver iodide flares designed for atmospheric dispersion.

4. How much did the experiment cost?

The overall budget for the five planned sorties was ₹3.21 crore. The three trials conducted so far cost approximately ₹1.9 crore. Each sortie includes costs for aircraft, equipment, fuel, and scientific instrumentation.

5. Did it rain anywhere after the seeding?

Light drizzle — about 0.3 millimeters — was recorded in Noida and Greater Noida, but Delhi itself saw no measurable rainfall. Meteorologists confirmed that these minimal readings were within normal weather variability and not clear evidence of successful seeding.