Toxic smog engulfs India's capital after Diwali

A thick smog covers in Delhi following the Hindu festival of Diwali. The air quality dipped to the very poor early Monday, with authorities warning of further deterioration. Schools were shut across India's capital on Friday as a toxic grey smog engulfed the city.

The public health crisis has persisted for decades and researchers have blamed the smog for hundreds of thousands of premature deaths across India. The holy day coincides with the weeks when tens of thousands of farmers across north India set fire to their fields to clear crop stubble from recently harvested rice paddies. 

That practice is one of the key drivers of Delhi's annual smog problem, worsening the impact of vehicle and industrial emissions.