The World Health Organization has released its first global survey of air pollution with Asian cities heading the list of the world’s worst polluters. Results were measured in annual mean PM10, or particulate matter with diameter of 10μm or less. The WHO states that a healthy concentration of PM10 per cubic metre is twenty micrograms and below. According to the survey, Ahwaz in Eastern Iran is the world’s most polluted city with a concentration of PM10 per cubic meter of 372 micrograms.
Overall Asian cities fair poorly in the survey. The new findings show that Ulan Bator is now Asia’s most polluted capital, with a PM10 level of 279. Compared to the Mongolian capital, Beijing and New Delhi, with 121 and 198 respectively, seem almost pristine. That is, until you consider that Tokyo, with its population of nearly 13 million, has a PM10 level of 23. And, although perhaps an unfair comparison, the Asia region’s squeakiest clean capital Auckland manages a PM10 level of just 11.
The findings also expose the environmental gap between Asia’s oft-compared cities Hong Kong and Singapore. Hong Kong’s PM10 level of 50 is much higher than Singapore’s 32.
Of course air quality, and PM10 levels in particular, is not the only measure of pollution. The Blacksmith Institute, an international non-profit organization dedicated to pollution problems in low and middle income countries, publishes a list of the world’s most polluted places. Its report takes into account a number of pollution sources, focusing on the potential impact on the local population. Its 2007 report found that of the “top ten worst places” four were in Asia, two each in China and India. – Charley Lanyon