Breathing in urban India is hard: of the world's top twenty cities with the worst air, 13 of them are found in India, according to a new analysis by the World Health Organization (WHO). Despite the attention recently given to Chinese cities for atrocious air pollution, many of India's cities are actually worse when comparing annual averages of fine airborne particulates.
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The WHO looked at PM2.5 or airborne particulates less than 10 micrometers in diameter over a calendar year; PM2.5s are considered especially dangerous because they are easily respirated into the lungs leading to health problems such as lung cancer, heart disease, asthma, and bronchitis.
Surveying 1,600 cities in 91 countries, the WHO found that New Delhi's air was the worst in the world with average of 153 PM2.5 micrograms per cubic meter. Three other Indian cities—Patna, Gwalior, and Raipur—round out the top four, with Karachi, Pakistan as the fifth worse in the world.
None of China's cities came in the top 20. In fact, the Chinese city suffering from the worst air pollution was Lanzhou at number 36. Beijing, which gets a lot of media attention, is actually number 77.
The WHO says that air pollution should not be more than 10 PM2.5 micrograms per cubic meter to be deemed safe. But more than 1,100 of the cities on the list had levels of 11 or above. New Delhi air was more than 1,500 percent above the recommended level, and Beijing's nearly 800 percent. However the WHO cautioned that some of the world's most polluted cities may not be on the list.
"Many cities in the world, including some expected to be among the most polluted, do not collect information or report on its outdoor air quality. WHO therefore cannot compare cities based on their levels of outdoor air pollution," says the WHO.
Still the new analysis allows easy side-by-side comparisons and paints a broad picture of air pollution worldwide. Worryingly, the analysis found that 90 percent of the global urban population (based on these 1,600 cities) were exposed to unsafe air pollution.
Government scientists from India have bashed the analysis saying that New Delhi's levels were too high and Beijing's too low. But one of the scientists contested that New Delhi averaged about 110 micrograms over the year, which is still 1,100 percent above the recommended level and a level that would land it in the top 10.
Read more from our affiliate, Mongabay.
India traffic image via De Visu/Shutterstock.