It is the latest measure aimed at alleviating the toxic smog choking the lungs of 30 million residents of New Delhi and its surrounding territories -- consistently ranked as the world's worst capital for air quality.
Sachchida Nand Tripathi, a professor of sustainable energy engineering at the Indian Institute of Technology (IIT) at Kanpur, said aeroplanes equipped with seeding equipment or ground-mounted guns would be used to induce rainfall.
"Even very modest rain is effective in bringing down pollution," he told AFP.
Levels of PM2.5 pollutants -- cancer-causing microparticles that enter the bloodstream through the lungs -- often hit more than 30 times the World Health Organization's danger limits.
Breathing the poisonous air has catastrophic health consequences.
Prolonged exposure can trigger strokes, heart disease, lung cancer and respiratory diseases, according to the WHO.
The average city resident could die nearly 12 years earlier due to air pollution, an August report by the University of Chicago's Energy Policy Institute said.
The Delhi government has had to announce emergency school closures, and ban construction and entry of diesel vehicles into the city in a bid to improve the air quality.
- 'Wasteful expenditure'? -
But with these efforts bearing little result, the government has asked IIT Kanpur to prepare cloud seeding.
The weather modification, also known as "blueskying", involves releasing common salt -- or a mixture of different salts -- into clouds.
The crystals encourage condensation to form as rain.
Tripathi said cloud seeding has produced positive results, and "has not shown any adverse effect wherever it has been tried".
Authorities are waiting for clearances from various government bodies and favourable weather conditions before they can put the seeding plan into action, he said.
But it comes with a hefty price tag.
Exact costs have not been made public, but Indian media suggested it could be as high as 10 million rupees ($120,000) to seed 100 square kilometres (38 miles squared).
Environmental scientist Bhavreen Kandhari said cloud seeding was an "ineffective approach" to the pollution problem.
"It risks becoming a wasteful expenditure of public funds and valuable time," she told AFP.
Smog in Delhi is caused by a melange of factory and vehicle emissions, exacerbated by seasonal agricultural fires.
Eye-stinging pollution worsens during winter from October to February -- when colder air traps pollution -- and residents are advised to wear face masks outside at all times.
- 'Fleeting relief' -
India is not the first.
China extensively uses cloud seeding technology, spending billions of dollars to modify the weather to protect agricultural regions or improve air quality ahead of big events.
Other countries have also invested in the technology, including Indonesia and Malaysia.
Scientists in western India have successfully tried cloud seeding, which resulted in a 20 percent boost in rainfall, Tripathi said.
But Sunil Dahiya, an analyst with the Centre for Research on Energy and Clean Air, said artificial rain was not a "definitive solution" to air pollution.
"The relief it provides is fleeting, as the cessation of rain allows the re-entry of polluted air masses, swiftly elevating air quality back to hazardous levels," Dahiya told AFP.
Dahiya said emissions have to be reduced at their source for any long-term solution to the problem.
"Redirecting our efforts to this strategic approach is crucial for sustained and meaningful improvements in air quality," he said.
But Tripathi said it was a technology "worth trying", especially since other measures had failed.
Delhi set up its first smog tower two years back with much fanfare, a giant fan system sucking in air, but the $2 million structure has been lying defunct with experts saying its impact was limited to a mere 50-metre radius.
"When you have very little respite from very high pollution, and no other method works... what do you do?" Tripathi said.
Heat, disease, air pollution: How climate change impacts health
Paris (AFP) Nov 26, 2023 -
Growing calls for the world to come to grips with the many ways that global warming affects human health have prompted the first day dedicated to the issue at crunch UN climate talks starting next week.
Extreme heat, air pollution and the increasing spread of deadly infectious diseases are just some of the reasons why the World Health Organization has called climate change the single biggest health threat facing humanity.
Global warming must be limited to the Paris Agreement target of 1.5 degrees Celsius "to avert catastrophic health impacts and prevent millions of climate change-related deaths", according to the WHO.
However, under current national carbon-cutting plans, the world is on track to warm up to 2.9C this century, the UN said this week.
While no one will be completely safe from the effects of climate change, experts expect that most at risk will be children, women, the elderly, migrants and people in less developed countries which have emitted the least planet-warming greenhouse gases.
On December 3, the COP28 negotiations in Dubai will host the first "health day" ever held at the climate negotiations.
- Extreme heat -
This year is widely expected to be the hottest on record. And as the world continues to warm, even more frequent and intense heatwaves are expected to follow.
Heat is believed to have caused more than 70,000 deaths in Europe during summer last year, researchers said this week, revising the previous number up from 62,000.
Worldwide, people were exposed to an average of 86 days of life-threatening temperatures last year, according to the Lancet Countdown report earlier this week.
The number of people over 65 who died from heat rose by 85 percent from 1991-2000 to 2013-2022, it added.
And by 2050, more than five times more people will die from the heat each year under a 2C warming scenario, the Lancet Countdown projected.
More droughts will also drive rising hunger. Under the scenario of 2C warming by the end of the century, 520 million more people will experience moderate or severe food insecurity by 2050.
Meanwhile, other extreme weather events such as storms, floods and fires will continue to threaten the health of people across the world.
- Air pollution -
Almost 99 percent of the world's population breathes air that exceeds the WHO's guidelines for air pollution.
Outdoor air pollution driven by fossil fuel emissions kills more than four million people every year, according to the WHO.
It increases the risk of respiratory diseases, strokes, heart disease, lung cancer, diabetes and other health problems, posing a threat that has been compared to tobacco.
The damage is caused partly by PM2.5 microparticles, which are mostly from fossil fuels. People breathe these tiny particles into their lungs, where they can then enter the bloodstream.
While spikes in air pollution, such as extremes seen in India's capital New Delhi earlier this month, trigger respiratory problems and allergies, long-term exposure is believed to be even more harmful.
However it is not all bad news.
The Lancet Countdown report found that deaths from air pollution due to fossil fuels have fallen 16 percent since 2005, mostly due to efforts to reduce the impact of coal burning.
- Infectious diseases -
The changing climate means that mosquitoes, birds and mammals will roam beyond their previous habitats, raising the threat that they could spread infectious diseases with them.
Mosquito-borne diseases that pose a greater risk of spreading due to climate change include dengue, chikungunya, Zika, West Nile virus and malaria.
The transmission potential for dengue alone will increase by 36 percent with 2C warming, the Lancet Countdown report warned.
Storms and floods create stagnant water that are breeding grounds for mosquitoes, and also increase the risk of water-borne diseases such as cholera, typhoid and diarrhoea.
Scientists also fear that mammals straying into new areas could share diseases with each other, potentially creating new viruses that could then jump over to humans.
- Mental health -
Worrying about the present and future of our warming planet has also provoked rising anxiety, depression and even post-traumatic stress -- particularly for people already struggling with these disorders, psychologists have warned.
In the first 10 months of the year, people searched online for the term "climate anxiety" 27 times more than during the same period in 2017, according to data from Google Trends cited by the BBC this week.
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