Indian authorities are attempting to bring down air pollution in the capital after record levels in 2016

Like clockwork, the approach of winter in Delhi brings steadily worsening pollution levels in the city. It also heralds elaborate, sometimes hare-brained schemes to fix the problem.

Last year, the Indian capital tried showering the city with water from helicopters; but the aircraft were unable to fly in smog. When authorities used “smog cannons” to blast polluted streets with mist, air quality in those areas declined.

In October, environmental officials in the city will roll out the latest weapon in their war on pollution: more than 50 outdoor air purifiers at intersections on major roads.

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Tests in Mumbai showed the devices cut air pollution by about one-third, but only in the surrounding 20 metres. The units in Delhi will be more powerful, but experts are sceptical.

“It is like trying to air condition a room with the roof off,” says Alistair Lewis, a professor of atmospheric chemistry at the University of York. “There is very little evidence they make a difference to concentrations of pollution.”

Facebook Twitter Pinterest An air purifier which was installed for a trial period at a busy road junction in Delhi in 2010. Photograph: CHI-Photo/REX/Shutterstock

The outdoor purifiers are “a distraction”, says Anumita Roychowdhury, an executive director at the Delhi-based centre for science and environment. “We are saying, focus on the real action of cutting pollution at the source.”

And quietly, Delhi is doing just that, she says. In the past two years, central and state governments, as well as the country’s supreme court, have pushed through a range of policies to curb the dust, fumes and carcinogenic smoke that blankets the city year-round and grows more acute during winter months.

Nobody believes the air quality this winter will be good, but it could be better than the past two years – the worst on record.

“Reform processes have been set in motion,” Roychowdhury says. “If they are taken forward, then we can see a silver lining.”

Facebook Twitter Pinterest Anti-smog cannons were trialled in New Delhi last year. Photograph: Anadolu Agency/Getty Images

Results are already being seen, officials say. Monitoring stations show this year is cleaner so far than the past two. Last year’s winter was also marginally better than 2016’s, thanks to a graded-action plan that gradually bans sources of pollution such as coal-power plants and construction activity as the air quality declines.

“Because these things happened, the number of days with severe pollution levels were less than the previous winter,” Roychowdhury says.

At a monitoring station in the heart of Delhi’s old city, researchers are grappling with just how deadly the atmosphere has become. The facility is one of three in India that can measure pollution particles as small as 1 micro-metre – more than a hundred times thinner than a strand of human hair.

“These are the finest particles we are inhaling and can get deep inside the lungs,” says Gufran Beig, a joint director at the Indian institute of tropical meteorology, who oversees research at the stations.

The pollutants, labelled PM1, are so poorly understood that the World Health Organisation does not know how much exposure, if any, is safe. But the pollutants are likely from the most toxic sources: they is especially thick near traffic or heavy industry.

Facebook Twitter Pinterest Dust from a storm covers the horizon on the outskirts of New Delhi, India, Saturday, June 9, 2018. Photograph: Altaf Qadri/AP

The stations are already changing the way smog in India is understood. Research has revealed the pollution in Mumbai, though less dense than in Delhi, contains more PM1 particles. The air in the financial hub may could be deadlier than previously known.

“Although the mass concentration of pollutants in Mumbai is less compared to Delhi, the toxicity is more,” Beig says.

Sharp spikes in Delhi’s pollution often come from dust storms blowing in from the Gulf. But the city also exudes extraordinary quantities of car exhaust, construction dust and smoke, especially during the Hindu festival Diwali, when millions of firecrackers can be exploded in a single night.

A raft of policies have been implemented in the past year to plug these pollution sources. Emissions standards for cars are being tightened more quickly. Imports of pet coke, a dirty fuel the US was accused of dumping in India, have been banned. The city’s last remaining thermal coal power plant will be permanently shut next month.

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As is often the case in India, actually implementing the new policies will be a challenge. But they give the city a path forward, Roychowdhury says. “There is no reason why we can’t bend the curve, if these things take off.”

As the winter approaches and the air quality falls, those who can afford to do so are investing heavily in air purifiers. The American Embassy School, in the city’s leafy diplomatic enclave, has spent more than $1m in the past four years on nearly 60 air purification units on its campus.

“We can get the air down to a level you could use in a hospital operating room,” says Jim Laney, the school’s director.

Nearly 150 air monitors are arrayed throughout the school and can warn when the air quality suddenly drops. “So if a teacher leaves a door or window open, we will see a spike in air quality and we can go and investigate it,” he says.

Children less frequently play outdoors, the younger ones especially encouraged to spend their recess in new indoor play areas. But the school has not been able to completely insulate students from the city around them.

“We are restricted in, for example, putting a bubble over a soccer field or playground under the New Delhi municipal council’s regulations,” Laney says.

At north’s Delhi Queen Mary school, like the vast majority in Delhi, air purifiers are out of reach. When smog worsens, some kids wear masks in class. Little else can be done but hope authorities make progress against poisonous air.

“We do our best to educate them, but they are living in Delhi,” says Rachel Rao, a coordinator at the school. “They can only breathe the air around them.”