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.

Air quality in northern India has worsened over the past week, with New Delhi's AQI recording a reading of 465, classified as "severe plus category", on Sunday evening due to unfavourable meteorological conditions,

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.

Delhi's new action plan to combat rising pollution includes a ban on non-essential trucks, school closures, and remote work.