Shanghai, March 22 (BUS): Not a single country could meet World Health Organization air quality standards in 2021, according to a survey of pollution data in 6,475 cities on Tuesday, and smog rebounded in some areas after the COVID-related decline.
The World Health Organization recommends that annual average readings of small and dangerous airborne particles known as PM2.5 be no more than 5 micrograms per cubic meter after changing its guidelines last year, saying that even low concentrations caused significant health risks, according to Reuters.
But only 3.4% of the cities surveyed met the standard in 2021, according to data committed by IQAir, a Swiss pollution technology company that monitors air quality. As many as 93 cities experienced PM2.5 levels at ten times the recommended level.
“There are a lot of countries that are making great strides in the area of reduction,” said Kristi Schroeder, director of air quality science at IQAir. “China started with some very big numbers and it keeps declining over time. But there are also places in the world where the situation is getting significantly worse.”
The data showed that overall pollution levels in India worsened in 2021 and New Delhi remained the world’s most polluted capital. Bangladesh was the most polluted country, also unchanged from the previous year, while Chad ranked second after African country data was included for the first time.
IQAir said China, which has been waging a war on pollution since 2014, slipped to 22nd in its PM2.5 ratings in 2021, down from 14th a year earlier, with average readings improving slightly over the year to 32.6 micrograms.
Hotan, in the northwest region of Xinjiang, was the worst performing city in China, with average PM2.5 readings of over 100 μg, largely caused by sandstorms.
It ranks third in the list of the world’s most polluted cities after being overtaken by Hewadi and Ghaziabad, both of which are in India.
HF