Whatever the causes of the smog, by one ranking Delhi was not just the most polluted city in the world, but “nearly five times as bad as the second most polluted city, Dhaka,” in Bangladesh next door, as Shashi Tharoor, a leader of the opposition in Parliament and best-selling author, posted on X.

Every year when winter arrives, India's capital region is choked by smog and smoke. Experts say there are already solutions waiting to be implemented, but more political will is needed.

India's capital city of Delhi has virtually shut down as air pollution hit "severe plus" levels, according to Indian government officials in its pollution control authority.

Unhealthy

A toxic haze enveloped India's national capital on Wednesday morning as temperatures dropped and pollution surged, reducing visibility in some parts and prompting a warning from airport authorities that flights may be affected.

A thick blanket of toxic smog engulfed most parts of northern India on Monday and readings of air quality in the capital New Delhi hit their highest this year after dense fog overnight. Visibility dropped to 100 m (109 yards) in Delhi and Chandigarh,

Delhi is experiencing very poor air quality, with some areas reaching severe levels. The Air Quality Index numbers are above 300 and even above 400 in some locations. Lack of rainfall and emissions have worsened the situation.