With the air laden with particles and the city under a dense haze, the authorities of the Indian capital have activated their first cloud seeding test with an immediate objective: to force rainfall that will help clean the environment. The maneuver, coordinated with the Indian Institute of Technology in Kanpur, is conceived as a palliative measure in a scenario of chronic pollution.
The test was carried out with a light aircraft over the Burari area, north of New Delhi, to check operational coordination and weather conditions. According to official sources, if the weather is favorable, the capital could record artificial rain on October 29, a symbolic milestone in the search for rapid solutions to winter smog.
Delhi turns to cloud seeding to ease smog
The operation was carried out with a Cessna airplane that flew over sectors of the northern part of the city to assess windows of opportunity. Teams from the IIT Kanpur and the local environmental department, with the idea of integrating the Indian Meteorological Department into monitoring effectiveness and safety.
The capital, with more than 30 million, records episodes of severe pollution every winter due to a temperature inversion that traps cold air under a warm layer. Added to this are industrial emissions, heavy traffic and stubble burning in nearby areas, forming a cocktail that multiplies PM2,5 levels well above WHO standards.
In recent days, values of Air Quality Index around 292 for the city as a whole, with some stations exceeding the "very poor" and even "severe" threshold (readings as high as 403). During the Diwali festivities, fireworks added sulfur and nitrogen oxides, worsening the already delicate situation.
Along with cloud seeding, measures known as the spraying water on roads, traffic reduction, construction surveillance, and patrols against garbage and biomass burning. Even so, authorities admit that rain induction does not replace the structural air quality policies.
How does the technique work and what substances are used?
Cloud seeding introduces small particles into the cloud that act as condensation nuclei to promote the formation of ice droplets or crystals. This way, the cloud tries to precipitate some of the water already contained within it, accelerating a natural process when humidity and atmospheric dynamics allow it.
Historically, salts such as silver iodide or sodium chloride; techniques are also applied from the ground (generators) or from the air (airplanes, drones and flares). In the case of Delhi, official communications did not specify the concrete compound used in the test, a relevant fact that is usually confirmed after the testing phase.
It is important to emphasize that this intervention does not “create” rain out of nothing: it seeks to improve the eficiency by suitable cloudsIn practical terms, it is about gaining a few tenths or percentage points of precipitation if the cloud presents temperature and microphysics compatible.
What science says: effectiveness and limits
The scientific literature collects heterogeneous results: there are studies that, in very specific scenarios (for example, winter clouds in mountainous areas), indicate precipitation increases of up to 20%. Other studies detect modest or difficult-to-isolate effects against the natural variability of the atmosphere.
Specialists consulted emphasize that a cloud, under normal conditions, only a fraction precipitates of the water it contains. Seeding aims to activate additional nuclei so that a larger portion ends up falling as rain or snow, although the yield depends on temperature, cloud type, droplet size and updrafts.
In any case, there is no full consensus in the scientific community about the magnitude of the effect in each situation. Hence, the serious weather modification programs are accompanied by instrumental monitoring and evaluation before operational use.
Background and experiences in Asia
The modern technique dates back to the work of the chemist and meteorologist Vincent Schaefer in the 1940s, when he showed that he could induce rain or snow by cooling and introducing nuclei into suitable clouds. Since then, seeding has been used to mitigate droughts, support firefighting or improve air quality episodes.
China has been pushing weather modification programs for years. In the Beijing 2008 Olympic Games Associated techniques have been employed to manage meteorology and, more recently, operations have been reported in arid regions such as Xinjiang with fleets of drones firing silver iodide rods and official results estimating precipitation increases around 4%.
India, for its part, is now entering a testing phase in the capital with academic support to measure feasibility, impact and costsThe institutional expectation is that, on specific days, an induced rain can provide a respite to millions of people exposed to levels of PM2,5 which are sometimes dozens of times higher than international recommendations.
In this context, those responsible recall that cloud seeding is a punctual complement and not a substitute for fundamental policies: emission control, electrification of transport, waste management and brakes on agricultural burning which every autumn triggers regional smog.
With these elements, the Indian capital is exploring a well-known meteorological tool, but its effectiveness is limited, while strengthens air controls and coordinates its technical agencies. The key will be to align atmospheric windows of opportunity with transparent protocols and evaluation. rigorous results to decide whether to continue or escalate it.
