As winter approaches and the monsoon retreats, Delhi braces for its annual descent into haze. Daylight dims under a heavy veil; mornings begin in a muffled grey. For millions of residents, the air turns into a threat. This year, the Delhi government has decided to deploy a controversial, high-stakes experiment: cloud seeding, or artificially induced rain, in the hope of sweeping away particulate pollution and delivering momentary relief.
The question looms: if rain is created on demand, will it breathe life back into Delhi’s strangled air, or will this gamble misfire?
The familiar descent into smog.
Delhi’s tryst with smog is long and fractious. For decades, policy debates, citizen protests and scientific warnings have circled the same sad truth: as winter deepens, the city turns into a haze chamber. The relative clarity of the monsoon gives way to months in which emissions accumulate, winds slacken, and air stagnates.
Seasonally, Delhi also incurs smoke from crop residue burning in Punjab, Haryana and Uttar Pradesh, which drifts into the capital when the winds align. Over recent years, Delhi has logged many consecutive days with AQI in the “severe” or “very poor” categories during November and December, with fine-particle concentrations sometimes several times above the WHO’s safe guideline.
The numbers are stark. On the worst days, PM 2.5 readings have crossed 500 or more micrograms per cubic meter, levels at which the entire city is placed on emergency alert. Visibility can drop to tens of metres; roads disappear into a milky grey screen. Photos of India Gate or Lutyens’ Delhi half-hidden in foggy haze have become annual staples in media.
For citizens, it is more than a spectacle: it is suffocating, grinding, unavoidable. Masks, indoor purifiers and medical advisories become part of daily life. The air grows heavy, the scent of cold stubble smoke and diesel lingers, and residents begin every inhalation with trepidation.
The health stakes
The damage is not just cosmetic. Delhi’s winter smog carries a heavy health burden, especially on children, the elderly, people with pre-existing respiratory or cardiovascular diseases, and the socioeconomically vulnerable.
Long-term exposure to fine particulate matter (PM 2.5) is a known risk factor for ischaemic heart disease, stroke, chronic obstructive pulmonary disease (COPD), lung cancer and other illnesses. Studies estimate that ambient air pollution contributes to hundreds of thousands of premature deaths annually in India.
In Delhi, episodes of extremely poor air quality routinely trigger surges in hospital visits for respiratory ailments — asthma attacks, bronchitis, and infections — and exacerbate cardiovascular stress. In research published across public health journals, spikes in pollution are correlated with increased admissions to emergency departments, and elevated mortality in the most vulnerable. Doctors speak of “smog season” as a medical crisis: outpatient departments fill with patients suffering from chest tightness, wheezing, persistent cough, and, in severe cases, acute exacerbations of chronic lung disease. The logic behind
exploring cloud seeding is that a few well-timed rains might cleanse the air when it is at peak danger, offering a temporary respite in the worst months.
Several tools, limited success
Delhi’s anti-pollution strategies have been numerous and ambitious. Over the years, authorities have tried demand controls, supply fixes, emergency protocols and regional coordination. Yet by and large, winter smog remains recalcitrant. One of the most visible measures has been traffic curbs like the odd–even scheme, where private vehicles alternate days based on plate numbers. The idea is simple: fewer cars should mean fewer emissions. In practice, the gains often dissipate after the restrictions end; many emissions emerge from background industrial or regional sources, making local traffic cuts only part of the answer.
Another set of tools targets dust and construction. During high pollution days, authorities ban construction, issue fines, water roads, deploy mist cannons and urge site contractors to cover materials. While such interventions help locally, enforcement is uneven, and dust still seeps through.
On the regulatory side, stricter emission norms for vehicles, phased retirement of old diesel engines, conversion to cleaner fuels in public transport, and even restrictions on the use of diesel generators under emergency protocols. But the growth of vehicles, continued industrial emissions, and legacy polluting units have often undermined gains.
The Graded Response Action Plan (GRAP) is Delhi’s built-in emergency kit. As pollution forecasts or observed AQI cross thresholds, GRAP triggers escalating measures — like shutting down brick kilns, limiting diesel use, banning construction, and curtailing traffic. Yet GRAP is reactive by nature: it applies after pollution levels are already high, rather than preventing buildup. Moreover, many polluting sources lie outside Delhi’s jurisdiction or are regional, so local actions often fall short against transboundary inflows.
Perhaps the chronic limitation is this: the very worst pollution days emerge not because emissions suddenly spike, but because meteorology locks the air in. Even moderate emissions become lethal under calm, stable skies. Thus, structural reforms (cleaner fuels, industrial controls, better waste management, and agricultural residue policies) are necessary — but slow to yield results. For the public, delay is hazardous. That is where the cloud seeding proposal enters the frame — not as a replacement, but as a complementary experiment, a hopeful intervention when all else stagnates.
The cloud seeding experiment
In May 2025, the Delhi cabinet cleared an experimental cloud seeding programme designed around five trial sorties on the periphery of the city. The announced budget was about Rs 3.2 crore, with approximately Rs 55 lakh allocated per flight plus logistics. The idea involved the fact that when meteorological conditions were favourable, an aircraft would fly through cloud systems on the fringes, releasing seeding agents to nudge precipitation, thereby helping wash away suspended particles in the air.
The government identified IIT Kanpur as the technical lead. Importantly, the plan explicitly restricts flight paths to avoid central Lutyens’ Delhi and airspace near the Indira Gandhi International Airport. The project is pitched as a modest, scientifically guided trial rather than a full-scale rainmaking operation.
“This is a scientific intervention to combat air pollution. If successful, it could become a game-changer in Delhi’s environmental strategy, particularly during the high-pollution post-monsoon season,” said Delhi Environment Minister Majinder Singh Sirsa.
Yet from the start, timing proved elusive. The onset of the monsoon in early July derailed initial plans. Officials, citing active cloud cover that would make seeding signals impossible to attribute, postponed the flights. By mid-July, the target window shifted, with Environment Minister Manjinder Singh Sirsa announcing that the trials would happen in September when clouds would be retreating but still present.
Through late summer, obtaining regulatory clearances proved arduous. The programme required no-objection certificates from the DGCA (aviation regulator), AAI (airport authority), Ministry of Defence, and environment agencies. Only after intense interagency coordination did the push gain traction.
In late September 2025, the DGCA granted permission for IIT Kanpur to operate a Cessna 206H (VT-IIT) from October 1 through November 30. Protocols restrict flights to visual flight rules, require coordination with air traffic control, prohibit aerial photography, ban foreign crew participation and restrict sorties to non-prohibited zones. On September 26, the Delhi government signed a Memorandum of Understanding with IIT Kanpur, formalising the undertaking. The first trials are now expected to begin in October, weather permitting.
Officials emphasise that the aircraft will remain on standby — no seeding will occur unless real-time meteorological data, cloud depth, moisture and stability metrics all align. The prime goal is not heavy downpours but measurable precipitation under controlled conditions.
Delhi’s gambit is tightly bounded: a handful of sorties, cautious regulatory guardrails, and a narrow seasonal window.
The global record and its caveats
Cloud seeding is not new, and many countries have tried rainmaking in different climates, with varying degrees of success and scientific contention. In the United States, many states run cloud seeding programmes, especially in dry mountain or snowpack regions. A 2024 US Government Accountability Office (GAO) review summarised literature and cautioned that evidence remains limited and that efficacy is context-dependent.
China maintains one of the world’s largest weather modification networks. In the United Arab Emirates, cloud seeding is part of a national water policy. Some local research claims enhancements of up to 30–35% in precipitation under favourable conditions, though those claims are contested and depend heavily on baseline moisture.
In India, there is precedent. An 11-year “warm cloud modification” experiment in Maharashtra (covering monsoon clouds) seeded salt particles (rather than ice nucleators) and reported rainfall enhancements of up to 24% under favourable cloud conditions.
Yet many seedings fail to produce statistically robust gains, and many of the more ambitious claims are not backed by strong, peer-reviewed control designs. The history of cloud seeding is peppered with optimism, scepticism and calls for better experimental rigour only under favourable meteorology, with good instrumentation and with modest expectations.
Is rain enough to clear Delhi air?
Delhi’s promise of artificial rain raises both hope and scepticism among scientists and observers. “It’s not yet clear whether this will have any real impact on Delhi’s air quality during the winter months,” said Anumita Roychowdhury, executive director, research and advocacy at the Centre for Science and Environment. “At that time of year, the weather conditions are such that pollutants get trapped close to the ground, making it extremely difficult for them to disperse.
Even if cloud seeding manages to trigger some rain, the effect will be very short-lived. It’s a temporary and very expensive measure. Year after year we see that even during the monsoon, pollution levels rise again during dry spells between rainfall — so it’s unrealistic to expect a sustained improvement from artificial rain. The pollution will simply bounce back once the rain stops. This is not a solution at all. That money and effort would be far better spent on cutting emissions at the source.” On the optimistic side, for residents choking in thick haze, even a few hours of clearer air could offer crucial relief.
A relief, but not the cure
Delhi’s air crisis is rooted in centuries of settlement, industrialisation and modern growth. Every winter, citizens feel that crisis anew: choking, coughing, and scarcity of clean air. The temptation to reach into the skies and force rain is powerful. What the government now proposes is not the grand promise of “rain on demand” but a measured experiment, a probe into whether nature’s moisture can be coaxed to give the people some breathing space.
If a few aircraft sorties in October manage to produce credible rainfall, and if that rainfall measurably reduces particulate pollution below health danger thresholds, even for a few hours, it would represent a breakthrough in Delhi’s seasonal battle. But that success must be earned with data, not narrative.
Afterall as the capital stands to launch its first artificial rain, citizens will watch the skies in hope.
