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Reuters
Reuters
SHANGHAI (Reuters) – Not a single country managed to meet the World Health Organization’s (WHO) 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 after changing its guidelines last year, saying that even low concentrations caused significant health risks. But only 3.4% of the surveyed cities met the standard in 2021, according to da…
