[image: article video]
NEW DELHI z India has once again topped an annual list of cities with the worst air quality link in the world, according to a new report, while Chinese cities have continued to show improvements from the previous year.
Twenty-one of the world's 30 cities link with the worst air pollution link are in India, according to data compiled in IQAir AirVisual's 2019 World Air Quality Report, link with six in the top ten.
Ghaziabad, a satellite city of the capital New Delhi in northern Uttar Pradesh state, is ranked as the world's most polluted city, with an average PM 2.5 concentration measurement of 110.2 in 2019. That's far more than double the level which the US Environmental Protection Agency regards as healthy link -- it's nine times more.
And in November, a public health emergency was declared link after the air quality index (AQI) level exceeded 800 in certain parts of New Delhi, which was more than three times the "hazardous" level.
Researchers from IQAir -- a global air quality information and tech company -- gleaned data for the report from on the ground monitoring stations that measure levels of fine particulate matter, known as PM 2.5, per cubic meter.
The microscopic particles, which are smaller than 2.5 micrometers in diameter, are considered particularly harmful as they are small enough to enter deep into the lungs and cardiovascular system.
PM 2.5 includes pollutants such as sulfate, nitrates and black carbon. Exposure to such particles has been linked to lung and heart disorders and can impair cognitive and immune functions.
According to the World Health Organization, air pollution causes an estimated 7 million link premature deaths a year globally, mainly as a result of increased mortality from cardiovascular diseases, cancers and respiratory infections.
It is estimated that more than 80% living in urban areas which monitor air pollution are exposed to air quality levels that exceed WHO guideline limits, with low- and middle-income countries most at risk.
"Air pollution constitutes the most pressing environmental health risk facing our global population," the AirVisual report said.
South Asia continues to be of particular concern, with 27 of the 30 most polluted cities in India, Pakistan or Bangladesh. Pakistan's Gujranwala, Faisalabad and Raiwind, are among the ten most polluted cities, and the major population centers of New Delhi, Lahore, and Dhaka rank 5th, 12th and 21st respectively, according to AirVisual data.
Regionally, South Asia, Southeast Asia, and the Middle East are worst affected overall, with only six of 355 cities included meeting WHO annual targets, the report said.
However, South Asia has seen improvements from the previous year. National air pollution in India decreased by 20% from 2018 to 2019, with 98% of cities experiencing of varying levels of improvement. The report points to economic slowdown, favorable weather conditions, and efforts towards cleaning the air as reasons behind the decrease.
For example, the most polluted city, Ghaziabad, had an average AQI of 110.2 this year. But in 2018 it was 135.2 and 144.6. in 2017.
The report also points India's launch of the country's first National Clean Air Programme (NCAP) which aims to reduce PM 2.5 and the bigger particulate PM 10 air pollution in 102 cities by 20-30% by 2024 compared to 2017 levels. - CNN