Residents in India's northern states woke up to another day of poor air quality on Tuesday, as a layer of dense fog shrouded most of the region, and pollution in the capital Delhi remained severe. India battles air pollution every winter as cold,

In several areas, pollution levels were more than 50 times higher than the World Health Organization's recommended safe limit.

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.The smog, a toxic blend of smoke and fog,