Delhi is not the world’s most polluted city anymore, the World Health Organisation’s urban air quality database shows.
Zabol in Iran leaped ahead of the national capital, which is now ranked at number 9.
Indian cities of Gwalior, Allahabad, Patna and Raipur are more polluted than Delhi in terms of PM 2.5 concentrations.
The 2014 WHO report had said that Delhi was the most polluted in the world.
The WHO’s database has 3,000 cities from 103 countries on its list. In its 2014 report, WHO had included only 1,600 cities.
The average PM 2.5 concentration in Delhi is 122 micro gram per cubic metre as per the latest report as opposed to 153 micro gram per cubic metre in the 2014 report.
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. The WHO says more than 7 million premature deaths occur every year due to air pollution, 3 million of them due to outdoor air quality.
According to the report, 10 out of the top 20 most polluted cities are in India. In 2014, this number was 13.
Maria Neira, head of public health, environmental and social determinants of health at the WHO, praised the government for developing a national plan to deal with the problem when others have been unable to.
It is important to note that Delhi’s data dates back to 2013, and is collected from 10 stations. Data from most other Indian cities dates back to 2012.
“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,” Neira said.
WHO uses data from various government and research organisations for the database and uses an average from stations as the final measurement.
On average, pollution levels worsened by 8% between 2008 and 2013, although most cities in rich countries improved the state of their air over the same period.