IQAir tracks air quality across the world.

Data showed the bad quality of air in all 83 Indian cities exceeded the World Health Organization’s air quality guidelines by more than 10 times.

Begusarai in Bihar emerged as the world's most polluted metropolitan area.

The city registered an average annual PM2.5 concentration of 118.9.

It is 23 times more than the figure set in WHO guidelines.

Delhi, which has been struggling to contain the air pollution problem for years now, stood as the capital city with the poorest air quality.

The report showed India was home to the four most polluted cities in the world.

For this year’s report, data from more than 30,000 air quality monitoring stations across 7,812 locations in 134 countries, territories, and regions were analyzed by IQAir’s air quality scientists.

"A clean, healthy, and sustainable environment is a universal human right. In many parts of the world the lack of air quality data delays decisive action and perpetuates unnecessary human suffering. Air quality data saves lives. Where air quality is reported, action is taken, and air quality improves," states Frank Hammes, Global CEO, IQAir.

As per  World Health Organization's website, combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually.

Aidan Farrow, Sr. Air Quality Scientist, Greenpeace International said: "IQAir’s annual report illustrates the international nature and inequitable consequences of the enduring air pollution crisis. Local, national, and international effort is urgently needed to monitor air quality in under-resourced places, manage the causes of transboundary haze, and cut our reliance on combustion as an energy source."

“In 2023, air pollution remained a global health catastrophe. IQAir’s global data set provides an important reminder of the resulting injustices and the need to implement the many solutions that exist to this problem," Aidan Farrow said.

As per the report, the most polluted major U.S. city was Columbus, Ohio. Beloit, Wisconsin was the most polluted city in the U.S.

Las Vegas, Nevada was the cleanest major city in the U.S.

For the first time in the history of the report, Canada was the most polluted country in Northern America, with the region's 13 most polluted cities located within its borders.

The top five most polluted countries in 2023 were

Bangladesh (79.9 µg/m3) more than 15 times higher than the WHO PM2.5 annual guideline

Pakistan (73.7 µg/m3) more than 14 times higher than the WHO PM2.5 annual guideline

India (54.4 µg/m3) more than 10 times higher than the WHO PM2.5 annual guideline

Tajikistan (49.0 µg/m3) more than 9 times higher than the WHO PM2.5 annual guideline

Burkina Faso (46.6 µg/m3) more than 9 times higher than the WHO PM2.5 annual guideline

A total of 124 (92.5%) out of 134 countries and regions exceeded the WHO annual PM2.5 guideline value of 5 µg/m3.