Four of the five cities in the world with the worst air pollution are located in India, the World Health Organization (WHO) said on Thursday.
The report, that surveyed 3,000 urban areas, has found that only 2 per cent of cities in poorer countries have air quality that meets international safety standards, while 44 percent of richer cities do.
WHO experts acknowledge that India faces a “huge challenge”; yet many countries face a worse situation as they have no monitoring system and thus cannot be included in its ranking.
The dirtiest air was recorded at Zabol in Iran, which suffers from months of dust storms in the summer, and which clocked a so-called PM2.5 measure of 217. The next four were all Indian: Gwalior, Allahabad, Patna and Raipur.
India’s capital New Delhi was the survey’s ninth worst city, measured by the amount of particulate matter under 2.5 micrograms found in every cubic meter of air, with an annual average PM2.5 measurement of 122.
New Delhi was ranked worst in 2014 with a PM2.5 reading of 153. It has since tried to tackle its toxic air by limiting the use of private cars on the road for short periods.
Over 80 percent of people who live in cities worldwide breathe polluted air, increasing their risk of lung cancer and other life-threatening diseases, the report revealed.
Tiny particulate matter can cause lung cancer, strokes and heart disease over the long term, as well as triggering symptoms such as heart attacks that kill more rapidly.
According to the WHO, more than 7 million premature deaths occur every year due to air pollution, 3 million of them due to outdoor air quality.
Maria Neira, head of public health, environmental and social determinants of health at the WHO, praised India’s government for developing a national plan to deal with the problem when others have been unable to.
“Probably some of the worst cities that are the most polluted ones in the world are not included in our list, just because they are so bad that they do not even have a good system of monitoring of air quality, so it’s unfair to compare or give a rank,” she said.
Common causes of air pollution include too many cars, especially diesel-fueled vehicles, the heating and cooling of big buildings, waste management, agriculture and the use of coal or diesel generators for power.
On average, pollution levels exacerbated by 8 percent between 2008 and 2013, although most cities in rich countries improved the state of their air over the same period.
The WHO database has almost doubled in size since 2014, and the trend towards more transparency translated into more action to deal with the problem, Neira said.
“Urban air pollution continues to rise at an alarming rate, wreaking havoc on human health,” she added.
However, there was still very sparse data on Africa, she said.