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.
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.
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 in Asia on Thursday.
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 here wear the filter masks that sometimes appear in Beijing.