Gurugram Society Uses ‘Artificial Rain’ To Fight Air Pollution, Should Delhi Consider It Too?

Last Updated:November 12, 2024, 13:49 IST

The Delhi government has been pushing for artificial rain using cloud-seeding – the method of triggering rain by seeding clouds with salts – to fight the pollution, but the plan is yet to take off.

Videos of artificial rain at a housing society in Gurugram surfaced on social media last week while Delhi was engulfed by an apocalyptic smog after stubble burning, bursting of firecrackers, and other meteorological factors around Diwali pushed air pollution levels to new highs. Although the rain was artificially created using sprinklers, it offered a glimmer of hope to residents in NCR, even though there is no empirical evidence to suggest that it reduced pollution levels in the area.

The Delhi government has also been pushing for artificial rain using cloud-seeding – the method of triggering rain by seeding clouds with salts – to fight the pollution, but the plan is yet to take off. The government came up with the idea last year as well, but the plan did not materialise due to unfavourable weather conditions.

News18 spoke to eminent experts tracking air quality to understand if this artificial rain could be considered as an immediate solution for the capital’s winter problem since showers seem to improve the city’s air quality index (AQI) during monsoon.

Experts do not view artificial rain as a sustainable solution to pollution problems and point out that it may improve air quality slightly for some hours or a day or two depending on meteorological factors, wherever it happens. But once polluted particles settle in again from nearby areas, the AQI will go up again, resulting in waste of resources and energy deployed to induce artificial rain.

There has been little global research on using artificial rain to lower pollution levels in cities like Delhi. However, during the 2008 Beijing Olympics, China used cloud-seeding methods to induce rain, thereby, clearing smog, reducing pollution levels and improving visibility and weather conditions for the opening day event.

Will Artificial Rain On Diwali Help Bring Down Pollution Levels?

For Delhi, air quality scientists said artificial rain can be experimented in extreme situations like on Diwali day or after for a shorter duration around sensitive locations when pollution levels reach extreme levels.

Even though artificial rain might cut down pollution to some extent, Dr R Subramanian, Sector Head, Air Quality at Center for Study of Science, Technology & Policy (CSTEP), said that the relief will only be temporary since other sources like wood burning, vehicular exhaust, industrial pollution, are going to pollute the city unless they are blown out by wind or washed out by rain.

“There have not been a lot of studies done on this. Some particles formed clouds and they rained down. Once raindrops come down, they hit other particles and they wash them out. In theory regarding cloud seeding, authorities are hoping once raindrops come down, they will scavenge out pollution particles from below. It might or might not work. Even if it does work, it will be a very temporary solution. If we don’t cut down the source of pollution, pollution will keep coming back after a while. Do you want to just keep on pouring rain again and again,” he asked.

Sunil Dahiya, Founder and Lead Analyst, Envirocatalysts, said there is no concrete scientific evidence anywhere globally which has approved measures like artificial rain to be effective to clean air at a city scale for sustained durations.

“Solutions like artificial rain can be implemented in extreme situations like on Diwali day or after for a shorter duration around sensitive locations. As soon as artificial rain stops, polluted particles from nearby areas will come in. Any such measure either to induce artificial rain or using water sprinklers in any form or even smog towers are not solutions to air pollution,” he said.

However, he also pointed out different reasons that might help to bring down pollution levels in case of rain on Diwali, like fewer people will go out to burst firecrackers and move around the city in their vehicles, cutting emission loads. “A day after that the impact of rain would have gone away and within a day we would have seen the same pollution level which was there earlier,” Dahiya said.

Cloud Seeding: How It Works?

Cloud seeding involves introducing various chemical agents, such as silver iodide, dry ice, and sometimes table salt, into clouds to enhance their density and improve the likelihood of rainfall.

One of India’s most eminent climate change and air quality scientists Sachchida Nand Tripathi, who is Dean of Kotak School of Sustainability at IIT Kanpur, highlighted the need for effective cloud-seeding to induce rain, which would then help clean the atmosphere to a certain extent.

“The issue is whether seeding can result in rain. It depends on many conditions. Some of them are not under your control. Outcome of seeding is not certain. For this you have to experiment and then only you can perfect the art,” he said.

Elaborating further, Tripathi, who is actively involved in cloud seeding projects at IIT Kanpur, said, “The advantage with seeding is that if you are able to successfully seed and thereby alter somewhat cloud characteristics which can result in rain, then certainly it can clean the atmosphere to a certain extent. We have developed seeding material at IIT Kanpur. You have to have effective seeding. Clouds form on some seeds. They don’t form without seeds, which are particulate matter. If there is more particulate matter, then there will be more droplets. Then depending on the nature of the seed, you can alter somewhat cloud characteristics. You inject seed at a certain level height under certain conditions so it accelerates the rain formation process in clouds. Once you seed it, rain may happen. We had installed seeding equipment on our aircraft and sprayed it on clouds. This is what we did in Kanpur, and rain happened.”

How Much Will Artificial Rain Cost?

Manoj Kumar, Analyst at Centre for Research on Energy and Clean Air (CREA), said there are significant limitations of artificial rain and the cost is substantial for such an experiment that does not address the fundamental causes of air pollution.

“Artificial rain has significant limitations. Not all clouds are seedable, and even when they are, there is no control over where the rain falls or how much rain occurs,” he said.

He said it is estimated to cost around Rs 1 crore for every 100 square kilometres of area. “Given that Delhi covers 1,400 square kilometres, the total cost for even a temporary improvement could exceed Rs 14 crore. It would be more prudent to invest in long-term measures that target pollution at its source,” he added.

Need For Sustainable Solutions

Prakash Doraiswamy, Program Director, Air Quality, WRI India, said the only way to ensure sustained improvement of air quality over the long term is to reduce emissions at the source. He underlined that Delhi-NCR and the entire Indo-Gangetic Plain (IGP) should work collectively to reduce emissions from all source sectors all year.

Echoing similar views, CREA Analyst Manoj Kumar said Delhi must prioritise proactive measures to curb pollution, focusing on reducing emissions from key sources such as transportation, power plants, and industrial activities.