No country met WHO (World Health Organization) air quality standards in 2021, according to a survey presented this Tuesday (22) on pollution data in 6,475 cities.
The WHO recommends that average annual readings of small particles in the air, known as PM2.5, should not record more than five micrograms per cubic meter. The guidelines were amended last year on the grounds that even low concentrations pose significant health risks.
But only 3.4% of cities surveyed met the standard in 2021, according to data from IQAir, a Swiss technology company that monitors air quality. About 93 cities had PM2.5 levels ten times higher than recommended.
“There are many countries that are making big strides in reduction,” said Christi Schroeder, air quality science manager at IQAir. “China started with some very large numbers and they continue to decline over time. But there are also places in the world where it is getting significantly worse.”
India’s overall pollution levels worsened in 2021, and New Delhi remained the world’s most polluted capital, the data showed. Bangladesh was the most polluted country, also unchanged from the previous year, while Chad was in second place — data from the African country were included for the first time.
China, which has been at war on pollution since 2014, dropped to 22nd in the PM2.5 ranking in 2021, down from 14th place a year earlier, with average readings improving slightly to 32.6 micrograms, IQAir said.
Hotan, in the northwest region of Xinjiang, was the worst performing Chinese city, with average PM2.5 readings of over 100 micrograms, largely caused by dust storms. The city has dropped to third place on the world’s most polluted list after being overtaken by Bhiwadi and Ghaziabad, both in India.
