Shanghai – World Health Organization's (WHO) revealed that not a single country managed to meet the air quality standard in 2021, a survey of pollution data in 6,475 cities showed on Tuesday, and smog even rebounded in some regions after a COVID-related dip.
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. The guidelines were changed last year, as even low concentrations were found to cause significant health risks.
Only 3.4% 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.
India's overall pollution levels worsened in 2021, where New Delhi remained the world's most polluted capital. Bangladesh remained the most polluted country, unchanged from the previous year. Chad ranked second after the African country's data was included for the first time.
China, which has been fighting pollution since 2014, fell to 22nd in the PM2.5 rankings in 2021, down from 14th place a year earlier. The country’s average readings improved 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, in India.
-Reuters