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.

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.

Questioning the response of the Centre, she said, “The Prime Minister is not even in the country... Seven states, more than one-third of the country is facing a medical emergency.

Unhealthy

India said on Sunday that it would tighten restrictions including on construction activities and vehicle movements in New Delhi and surrounding areas from Monday to combat worsening air quality.

Most of India’s coal-burning plants are set to again fall short of a major pollution target, adding to the deadly smog that’s enveloped large parts of the country.

Delhi was listed as India's most polluted city Thursday as a weeks-long air quality crisis gripping northern India has shown few signs of letting up.

Residents of the national capital breathed in despair on Saturday, with the air quality plunging back to the 'severe' category as average Air Quality Index (AQI) pegged at 412.