‘Cloud seeding is just cosmetic’

Amid the ongoing debate over air quality data manipulation, Delhi once again lies shrouded in toxic smog as winter sets in. With citizens, environmentalists, and political leaders taking to the streets to demand their fundamental right to clean air, questions arise: can pollution data really be tampered with, and are temporary fixes, such as anti-smog guns, mist sprays, and artificial rain, enough to clear the city’s foul air?

In conversation with MUSKAN BHATIA of The Statesman, Anumita Roychowdhury, Executive Director (Research and Advocacy) at the Centre for Science and Environment (CSE), explains why credible data is essential and why long-term, multi-sector action is the only real solution. Over the past two decades, she has led major policy campaigns on air pollution – especially vehicular emissions – and helped design clean air action plans in Indian and African cities, including the pioneering Right to Clean Air campaign. Edited excerpts:

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Q. In a recent interview, it was mentioned that air quality data can be manipulated by using water sprinklers around monitoring stations. What makes you say that?

A: Claims about the potential manipulation of air quality data through water sprinkling near monitoring stations have been reported in the media and are worrying. The key question, however, is whether such actions can actually alter the readings. As of now, we have not conducted any independent assessment to determine the extent to which water sprinkling near monitoring stations might influence air quality data. It is an aspect that certainly needs examination. That is why we have emphasized the importance of regular audits of air quality monitoring stations – to ensure that proper monitoring protocols are followed and to identify any external factors or activities around the stations that could affect the readings.

Q. There were reports of missing air quality data on the night of Diwali . If data manipulation or gaps do occur, why is it important to address them?

A: When such large investments are made in real-time air quality monitoring systems, it is crucial to ensure that protocols are strictly followed so the data remain reliable, credible and continuous. There should be no missing information – monitoring stations must operate to deliver authentic, validated data at all times. Accurate data is essential not only for policy decisions but also for informing the public so that people can take appropriate precautions when pollution levels rise.

Q. Do you think the current Winter Action Plan is effective enough to tackle Delhi’s toxic air? If not, why?

A: Our position is clear – Delhi’s air pollution problem can only be solved through year-round and sector-specific action. Consistent efforts across the year help build the infrastructure, systems, and services needed to cut emissions at the source. In contrast, the Winter Action Plan is more of an emergency response, activated only when pollution spikes due to seasonal changes. These measures are temporary by design and cannot bring sustained improvement in air quality.

Q. When you talk about t temporary measures, does that also include action against stubble burning in Delhi and neighbouring states?

A: Stubble burning is an episodic issue, but it is different from the temporary emergency measures we refer to – such as using smog guns, sprinkling water to control dust, halting construction for a few days, or restricting truck entry into Delhi. Crop burning happens only during a short period when farmers switch from one crop to another. To address that, we need systemic, long-term solutions – not short-term fixes. This includes providing farmers with machines to mix crop residue into the soil instead of burning it, and developing infrastructure to convert stubble into materials or biofuels for industry. That way, the residue becomes an economic resource rather than waste, giving farmers a real incentive not to burn it. The solutions are already known – the challenge now is how quickly we can scale them up to eliminate stubble burning altogether.

Q. While CAQM highlights its field inspections and penalties against farmers, do you think this focus shifts the attention away from other more significant sources of pollution in Delhi?

A: We must not confuse the two issues. Tackling stubble burning requires its own set of in-situ and ex-situ strategies. In-situ measures involve providing farmers with subsidized machines to mix crop residue into the soil instead of burning it. Ex-situ solutions mean collecting stubble and converting it into biomass pellets, bio-CNG, or other fuels that industries can use. These strategies must be implemented properly – but they should not be mixed up with the broader pollution control measures needed for other sectors. Crop burning is a seasonal issue, whereas Delhi’s air pollution persists year-round due to vehicles, industries, power plants, construction, and waste burning. Since vehicles are now the top contributor, Delhi must push for an ambitious zero-emission electric vehicle programme, expand public transport, and create better walking and cycling infrastr ucture to reduce dependence on private vehicles. Similarly, to stop waste burning , municipalities must ensure 100 per cent waste collection, segregation, and remediation of legacy dumpsites. All this demands continuous, year-round investment in infrastructure and systems to control emissions from every source – not just seasonal ones like stubble burning.

Q. What is your take on artificial cloud seeding – the solution that the Delhi government is exploring to curb the city’s air pollution crisis?

A: That is only a temporary and a cosmetic measure with no effective durable impact. It is also very expensive. Moreover, there is no guarantee it will even work – artificial rain requires several specific conditions to align. And even if those conditions are met and rainfall does occur, the relief will be short-lived. After the initial washout effect that lasts a few hours or at most in a couple of days, pollution levels will rise again. So why should we spend such a huge amount of money on a stopgap measure that offers no lasting impact?

Q. How does Delhi’s air pollution problem compare with that of a historically polluted city like Beijing? What lessons can Delhi learn from it?

A: To begin with, it is not that Delhi has not made efforts to tackle its pollution problem. The city has already shut down all its coal-based power plants. Polluting fuels such as coal, pet coke, furnace oil, and tyre oil have been banned in industries across the city, which have largely transitioned to cleaner natural gas. On the transport front, both public and commercial vehicles have shifted from diesel to CNG. The city has also begun electrifying its vehicle fleet and enforcing Bharat Stage VI emission standards. These are no small achievements. Thanks to such measures, Delhi’s long-term pollution trend is, in fact, on a decline. However, despite this progress, pollution levels remain alarmingly high. Delhi still needs another 60 per cent reduction in pollution to meet the clean air standard. To bring about the kind of drastic improvement seen in Beijing and other global cities, Delhi will have to act with far greater scale, speed, and strictness – and across all pollution-causing sectors, not just a select few. Like Beijing, Delhi also cannot fight this battle alone. Air pollution does not respect state boundaries. For Delhi’s efforts to yield real results, similar measures must be implemented across the entire Indo-Gangetic Plain. Beijing gained only after extending stringent anti-pollution actions beyond the city to 26 surrounding provinces. That kind of coordinated, regional approach is exactly what Delhi now needs.