Shrayan Sen
Delhi’s ambitious attempt to generate artificial rain through cloud seeding to combat worsening air pollution failed to yield measurable results. The ₹3.2-crore operation, conducted in collaboration with IIT Kanpur, aimed to trigger rainfall that could help wash out suspended pollutants from the city’s smog-laden atmosphere.
The experiment took place on tuesday 28th October, when an aircraft flew across Delhi-NCR releasing silver iodide and sodium chloride flares into moisture-bearing clouds. However, the skies remained largely dry, with only trace amounts of rainfall recorded in Noida and Greater Noida.
The experiment and its outcome
According to officials involved in the project, the attempt failed because the atmospheric moisture content was too low to allow the seeded particles to form raindrops.
“Ideally, relative humidity levels need to be above 60% for successful seeding,” said IIT Kanpur Director Manindra Agrawal. “On the day of the flight, the humidity was only around 20%, making rainfall scientifically impossible.”
Data from meteorological observations also confirmed that the clouds over Delhi during the operation were weak and insufficient to sustain artificial rain.
How cloud seeding works
Cloud seeding is a weather modification technique that involves dispersing substances such as silver iodide, sodium chloride, or dry ice into clouds to encourage condensation and precipitation.
Many countries use it to enhance rainfall in drought-prone areas or to disperse fog. In Delhi’s case, the goal was to clean the air by triggering a shower that could temporarily reduce the concentration of harmful particulate matter responsible for its thick smog.
Reaction from experts
Weather scientists noted that the effort was innovative but poorly timed. They explained that cloud seeding can only work when clouds are already rich in moisture and have sufficient vertical development. When humidity is too low, the particles released simply dissipate without forming raindrops.
Experts also pointed out that such experiments are probabilistic in nature. Even under ideal conditions, success rates for artificial rain remain between 30 and 40 percent globally.
Political reactions
The failed experiment quickly turned into a political flashpoint in Delhi.
Aam Aadmi Party (AAP) leader Saurabh Bharadwaj mocked the Bharatiya Janata Party (BJP)-led Delhi government’s artificial rain drive, saying, “Even Lord Indra isn’t with them.” He remarked that the government was preparing to claim credit for any natural rain that might occur later, joking that “Lord Indra will make it rain, but they will show it as their expense.”
Bharadwaj also commented that the government had rushed to create publicity around the operation, saying they thought it might rain soon and “decided to spice it up by creating artificial rain.”
Officials from the Delhi government responded by clarifying that the operation was a scientific pilot meant to test the feasibility of artificial rain in urban conditions. They maintained that such projects are experimental in nature and depend entirely on atmospheric conditions.
Lessons from global experiences
Delhi’s experience is consistent with the mixed results of cloud seeding observed worldwide. In some instances, such as operations in China and the United Arab Emirates, seeding coincided with excessive rainfall or flooding. In most others, it produced little or no measurable impact.
Scientists agree that cloud seeding cannot create rain in the absence of suitable clouds. It can only enhance existing precipitation under favorable conditions.
India’s past experience
India has experimented with cloud seeding since the 1950s, with projects conducted in states such as Maharashtra, Karnataka, Andhra Pradesh, and Tamil Nadu. These efforts have shown limited success.
The CAIPEEX (Cloud Aerosol Interaction and Precipitation Enhancement Experiment) project led by the Indian Institute of Tropical Meteorology demonstrated that artificial rain could be increased marginally when humidity, temperature, and cloud structure align perfectly.
Future plans
Despite the lack of success, the Delhi environment department is expected to review the data collected during the October trial with IIT Kanpur and consider another round of cloud seeding during the monsoon transition period in 2026, when atmospheric humidity levels are typically higher.
The Ministry of Earth Sciences is also studying the feasibility of creating a coordinated national framework for weather modification projects, to ensure scientific oversight and effective monitoring.
A sky full of lessons
Delhi’s artificial rain experiment ended without a drop, but not without lessons. Scientists reaffirmed that atmospheric conditions remain the deciding factor in any such operation. The episode has also shown how quickly a scientific trial can become entangled in politics.
As the smog lingers and debates continue, the city’s residents wait for real rain — the only kind that still comes without controversy.