NextBillion - An Initiative of the William Davidson Institute at the University of Michigan

Thursday, May 8, 2014

An effort by the World Health Organisation to measure pollution in cities around the world has found New Delhi admits to having the dirtiest air, while Beijing’s measurements, like its skies, are far from clear.

The study of 1,600 cities found air pollution had worsened since a smaller survey in 2011, especially in poorer countries, putting city-dwellers at higher risk of cancer, stroke and heart disease.

Air pollution killed about seven million people in 2012, making it the world’s single biggest environmental health risk, the WHO, a United Nations agency, said last month.

Thirteen of the dirtiest 20 cities were Indian, with New Delhi, Patna, Gwalior and Raipur in the top four spots. New Delhi had an annual average of 153 micrograms of small particulates, known as PM2.5, per cubic metre.

Beijing, notorious for the smog that has prompted some Anglophone residents to dub it “Greyjing”, was in 77th place with a PM2.5 reading of 56, little over one-third of Delhi’s pollution level.

WHO experts said the Chinese data was from 2010, the most recent year made available to them by China. But Beijing’s city government began publishing hourly PM2.5 data in January 2012.

A year after it started publishing data, Beijing’s air quality hit the “worst on record” according to Greenpeace, with a PM2.5 reading as high as 900 on one occasion