By Geeta Anand, New York Times

NEW DELHI — It isn’t just sweaters the kindergartners are wearing as they pour out of their classrooms onto the lawns of the American Embassy School in India’s capital city.

They are also wearing face masks.

The school does not require students to wear air filtration masks against the polluted air here, the worst in the world, in the estimation of the World Health Organization. But it has created what its director calls “a culture of acceptance” around wearing them.

It helps that they come in wild prints, made by a San Francisco company, many in fabrics from this year’s spring and summer collections of a top Indian fashion designer, Manish Arora. The Tiger’s Den, the campus store, has sold 800 this school year alone.

With expatriates and health-conscious Indians leading the way, residents of the Delhi metropolitan area of 25 million people are finally taking steps to protect themselves from the health-threatening atmosphere, as people in Beijing and some other heavily polluted Asian cities have already done.

New Delhi has long been covered with smog, but concerns escalated in early 2014, when the WHO study ranked New Delhi the worst. Then the U.S. Embassy here began making its air pollution data publicly available. A government pollution board stepped up its efforts to consistently measure and report its findings.

“The catalyst was the data becoming available,” said Paul Chmelik, director of the American school.

Shri Ram School, an elite private school, canceled sports day this winter because strenuous activity was deemed unsafe in such polluted air. The Delhi High Court asked the government to take action to improve the air, saying that living in New Delhi was like “living in a gas chamber.”

In January, the government restricted private cars in New Delhi to alternate days during a two-week test. To general surprise, the city’s famously lawless motorists actually followed the plan. The government plans to repeat the driving rules in April.

Air purifiers, from $50 to $1,000, have been flying off the shelves. And an Indian entrepreneur has been selling high-end designer air masks in Khan Market, among the most expensive retail areas in the world.

When the store’s owner, Jai Dhar Gupta, began selling the masks in January 2015, he estimated that he would sell about 10,000 a year. He sold that many in nine days.

A New Delhi native who used to own a call center company in San Francisco, Gupta developed a serious respiratory illness while training for a marathon in 2014, and recovered only after he began using an air filtration mask made by Vogmask. He became the company’s Indian distributor a year ago.

This winter, he says, he has been selling 500 to 700 masks a day from two retail stores in the New Delhi area as well as the school shop and a website.

The masks, when properly fitted, filter out 99 percent of airborne particles and are certified as personal protective equipment by agencies of the Chinese and South Korean governments, according to the company.

Vogmask has been manufacturing the masks in South Korea since 2012, and plans to begin making them in India this year. Reusable and made from a patented fabric, they retail for about $35, a price that is out of reach for the majority of Indians.

Foreign companies and nonprofits were among the early adopters. The Red Cross office in New Delhi bought masks for all of its employees this winter. Abid Malik, who works there, wears his mask while jogging.

“Before using it, I used to cough all the time,” he said. “Now I feel better.”

Surendra Singh, 49, got an air filtration mask when his nonprofit company distributed them to all 30 employees this winter. “We were all really panicked about the air,” he said.

He asked for the black mask with two air filters, which was advertised as the best design for active people, and wears it during his commute on three buses.

On a rainy morning last month, he was the only one on the bus with his nose and mouth covered. This made him the subject of intense curiosity and concern among commuters who still widely regard the masks with suspicion.

Asked why they were staring at him, most people said they were worried that he was sick, perhaps with tuberculosis. Others said they suspected he was mentally ill.

“Is he mad to wear that mask?” asked a 24-year-old hairdresser, Sonu Kumar.

As Singh got off the bus and began walking in the morning drizzle across a pedestrian footbridge toward his office, a 21-year-old student named Liaqat Ali was huddled with dozens of passengers under the bus shelter, continuing to stare.

“I think maybe he is so sick that he will die if he does not wear that mask,” Ali said.

That attitude has restricted sales in India, Vogmask’s co-founder Wendover Brown says. Her sales in China are four times as high.

At the American school, the administration held forums to discuss the pollution, created a committee to develop an action plan and asked the campus store to stock the masks.

A year ago, mask wearers were in the minority at school, but now most students wear them, says a parent, Aurelia Driver.

She sends her children to school with masks on their faces, attached by elastic bands so the masks can hang around their necks when indoors.

What began as a grim necessity has for many children become something of a fashion accessory, she said. “Having something fun and cool makes it something the kids want to wear,” she said. Another mother said she had bought them for her daughters after they pleaded for them, arguing that all the other kids had them.

The school has instituted a policy against students doing aerobic activity without wearing protective masks when the particulate levels reach the hazardous range.

That led the girls’ varsity soccer team to put in an order this month for masks for the entire team.

To Learn More:

            India has 13 of the 20 Most Polluted Cities in the World (by Karan Singh, AllGov India)

            Vehicles Over 15 Years Old Banned from Delhi Roads (by Karan Singh, AllGov India)

            Air Pollution Halves India’s Grain Production (by Karan Singh, AllGov India)

            India Launches Air Quality Index, But Tackling Pollution Needs Tough Choices (by Karan Singh, AllGov India)