NEW DELHI — An international effort to quantify air pollution levels has found that New Delhi's air is the most polluted in the world, followed by that of three other cities in India's central Hindi belt.
The findings by the World Health Organization confirm those of other experts, who for years have been puzzled about why so much international attention has focused on Beijing's troubled air quality rather than on what some say are equal or worse problems in South Asia.
"I am shocked at the extent of the problem they found in India," said Sundeep Salvi, director of the Chest Research Foundation in Pune, India. "This is incredibly bad, and there is a complete lack of awareness about it both amongst policymakers and the common man."
Thursday was typical in Delhi. The sun took much of the morning to penetrate the haze, and air quality machines measured levels of PM2.5 -- the small particles considered among the most dangerous for lung health -- exceeding 350. That is one of the highest levels recorded Thursday in Asia and twice as high as Beijing's peak for the morning, according to a Twitter post by the U.S. Embassy in the Chinese capital.
In Beijing, a pollution level as high as Delhi's would most likely have caused widespread concern. But in Delhi, almost no one seemed to notice. Few people in Delhi wear the filter masks that sometimes appear in Beijing, and even the wealthy rarely own air purifiers that are used widely in East Asia -- because few are even aware of the problem.
India is in the midst of national elections, and air pollution is rarely mentioned by leading politicians. At a recent embassy party, several people expressed astonishment that New Delhi's air was considered dangerous. One of the women, a marathon runner who jogs through Delhi's streets daily, said she had never noticed any problem with the air.
The WHO found that the annual mean for PM2.5 concentrations in Delhi was 153. Patna, Gwalior and Raipur followed Delhi for the worst air pollution readings. Delhi's reading was almost three times that of Beijing, whose annual mean in the report was 59.
There is no acceptable level of PM2.5, according to the U.S. Environmental Protection Agency.
A January story in The New York Times, which found that Delhi's air was at least twice as bad as Beijing's, led to weeks of headlines in India's largest newspapers and fierce denials among government officials. In the wake of the story, the Supreme Court of India agreed to consider a lawsuit demanding that action be taken to reduce smog.