Delhi was the world's most polluted capital in 2023, a Swiss-based air quality monitoring group has found.
IQAir said that India, of which Delhi is the capital, is also ranked as the third most polluted country in the world after its neighbors Bangladesh and Pakistan.
She added that the country's air has worsened since 2022, when it was the eighth most polluted country.
Air pollution is a serious problem in many Indian cities.
Experts say that rapid industrialization coupled with weak enforcement of environmental laws played a role in increasing pollution in the country.
India has seen a lot of development in the past few decades, but weak industrial regulation means that factories do not follow pollution control measures. Rapid construction also contributed to high pollution levels.
The IQAir report said India's average level of PM2.5 – a fine particulate matter that can clog the lungs and cause a range of diseases – was 54.4 micrograms per cubic metre.
Globally, Air containing 12 to 15 micrograms Each cubic meter of PM2.5 is considered safe to breathe, while air with values greater than 35 micrograms per cubic meter is considered unhealthy.
Delhi's air quality was worse than India's overall air quality, with the city's PM2.5 reading at 92.7 micrograms per cubic metre.
Delhi suffers from bad air all year round, but the air becomes especially toxic during the winter.
This is caused by various factors, including burning of crop residue by farmers in neighboring states, industrial and vehicular emissions, low wind speed and explosion of fireworks during festivals.
Last year, the government closed schools and colleges for several consecutive days due to toxic air.
Meanwhile, the northern Indian city of Begusarai and the northeastern Indian city of Guwahati are ranked as the two most polluted cities in the world.
Only seven countries have met the World Health Organization's annual guidelines for PM2.5, which have an annual average of 5 micrograms per cubic meter or less.
These include Australia, New Zealand, Iceland and Finland.
According to IQAir, this data was collected from more than 30,000 air quality monitoring stations in 134 countries, regions and territories.
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