Severe smog caused by pollution impacts New Delhi, other cities in northern India

A smoky haze blanketed New Delhi and parts of other northern Indian cities on Tuesday as low wintry temperatures set in, raising fears for the health of many millions of people.

In recent days, the Air Quality Index in the capital of 20 million people, where few use air purifiers or wear masks to protect themselves, has risen to "very poor" overall and sank to "severe" in some areas, according to data from the Central Pollution Control Board.

New Delhi resident Vivek Kumar Singh complained of breathing difficulties amid the worsening pollution, while traffic in Kanpur and Lucknow moved slowly due to reduced visibility on the roads.