And fireworks during Diwali, which take place at the same time, worsen air quality as low wind speeds trap pollutants in the lower atmosphere.

Concentrations of PM2.5 – a small, dangerous air pollutant – reached a high of 999 per cubic metre in parts of Delhi on Friday, according to government air quality monitoring data.

Some places recorded numbers close to or above 500, which is classified as “severe.”

A value between zero and 50 is considered “good” and between 51 and 100 is considered “satisfactory,” according to the Air Quality Index or AQI.

In an effort to curb pollution, the government has banned the sale and lighting of fireworks this year, but this does not seem to have deterred residents of the capital from taking the action.

A thick veil of smoke enveloped the city on Friday morning, and some residents were already complaining of itchy throats and watery eyes.

Many pictures and videos of the smoke divided on social media.

Others complained that the annual decline in air quality during Diwali was “always predictable.”

But the issue has also become a political problem, with some seeing it as an attempt to target Hindu festivals.

They argue that Diwali fireworks are an integral part of the celebrations and cannot be blamed for the hazardous air as Delhi suffers from severe air pollution all year round.

In fact, some people use Twitter to Share photos They set off firecrackers and declared that they wanted to celebrate Diwali.

Others, however, argue that the barrage of fireworks worsens the quality of air already laden with pollutants – and that fireworks are a relatively new addition to the Diwali festival, which is traditionally celebrated by lighting lights and praying to the goddess of wealth, Lakshmi, for prosperity.

Officials said the air would improve only slightly to “very poorly” on Sunday evening (July 11).

State air quality monitors estimate that stubble burning accounted for about 35% of Delhi's air pollution on Friday and is likely to increase over the weekend.

India has the worst air pollution in the world. As many as 22 of the 30 most polluted cities in the world are located in this country. India's toxic air kills more than a million people every year, according to experts.

Last year, Delhi recorded its highest PM2.5 concentration ever – 14 times the safe limit recognized by the World Health Organization (WHO).

A recent study found that 480 million people in northern India are exposed to “the world’s most extreme air pollution.”

It was also found that Delhi residents could live up to 10 years longer if air pollution could be reduced to the WHO guideline value of 10 g/m3.