These are 20 most polluted cities in the world; Rajasthan city tops the list
According to the report, Delhi's air pollution, ranked at number 4 globally, increased almost 15 per cent over the previous year.
As many as 35 of the 50 cities with the worst air quality were in India, with New Delhi continuing to be the world’s most polluted capital city for the fourth consecutive year in 2021, according to the World Air Quality Report, prepared by Swiss organisation IQAir, released on Tuesday.
According to the report, Delhi's air pollution, ranked at number 4 globally, increased almost 15 per cent over the previous year. However, the world's most polluted place is Rajasthan's Bhiwadi, followed by Uttar Pradesh's Ghaziabad. As many as 15 most polluted cities are in the country and mostly around the national capital, the study found.
Here are 20 most polluted cities in the world with their AQI
The IQAir report, published after a survey of pollution data in 6,475 cities across the world, also revealed that not a single country managed to meet the World Health Organization's (WHO) air quality standard in 2021, and smog even rebounded in some regions after a COVID-related dip.
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The WHO recommends that average annual readings of small and hazardous airborne particles known as PM2.5 should be no more than 5 micrograms per cubic metre after changing its guidelines last year, saying that even low concentrations caused significant health risks.
But only 3.4 per cent of the surveyed cities met the standard in 2021, according to data compiled by IQAir, a Swiss pollution technology company that monitors air quality. As many as 93 cities saw PM2.5 levels at 10 times the recommended level.
Bangladesh was the most polluted country, also unchanged from the previous year, while Chad ranked second after the African country's data was included for the first time.
China, which has been waging war on pollution since 2014, fell to 22nd in the PM2.5 rankings in 2021, down from 14th place a year earlier, with average readings improving slightly over the year to 32.6 micrograms, IQAir said.
Hotan in the northwestern region of Xinjiang was China's worst-performing city, with average PM2.5 readings of more than 100 micrograms, largely caused by sandstorms.
It fell to third on the list of the world's most polluted cities after being overtaken by Bhiwadi and Ghaziabad.
(With inputs from agencies)