WHO recommends that the annual average index of small and hazardous particles (also known as PM2.5) should not be more than 5 micrograms/m3 following a guideline change in 2021, even low concentrations of PM2.5 pose significant health risks.
However, only 3.4% of the cities surveyed will meet this standard by 2021, according to data from IQAir, the company that monitors Air quality of Switzerland. Up to 93 cities have PM2.5 concentrations 10 times higher than recommended levels.
Christi Schroeder, IQAir’s Director of Air Quality Science, said: “There are many countries that are making great strides in reducing emissions. China has previously had poor air quality with high concentrations. PM2.5 is very high, but this number is now decreasing over time. However, there are also parts of the world where the air quality is getting a lot worse.”
Morning fog covers New Delhi, India. (Photo: AP)
The data show that the level of air pollution India’s overall outlook worsens in 2021 and New Delhi remains the world’s most polluted capital. Thus, the Indian capital New Delhi is the most polluted capital in the world for the fourth year in a row. Bangladesh was the most polluted country, like the year before, while Chad ranked second after African country data was included in the survey for the first time.
Research by IQ-Air company also shows that the 6 most polluted cities in the world are in India. Meanwhile, half of the cities in this country have PM2.5 fine dust index 10 times higher than the recommended level of the World Health Organization. An estimated 1 million people die each year due to air pollution in India.
According to IQAir, China, which has been fighting air pollution since 2014, has dropped to 22nd place in the PM2.5 rankings in 2021, from 14th place a year earlier. with the average PM2.5 index improving slightly over the year, to 32.6 micrograms/m3.
Hotan in the northwestern region of Xinjiang is the city with the worst air quality in China, with an average PM2.5 reading of more than 100 micrograms/m.3mostly caused by sandstorms.
Now Hotan is in third place on the list of the most polluted cities in the world, behind Bhiwadi and Ghaziabad, both in India.
at Blogtuan.info – Source: vtv.vn – Read the original article here