Know reason behind toxic air quality of Delhi-NCR

Stubble burning is intentionally setting fire to the straw stubble that remains after grains, like paddy, wheat, etc., have been harvested. The practice was widespread until the 1990s, when governments increasingly restricted its use. Delhi was reeling under dangerously hazardous levels of pollution, the AAP chief had suddenly decided to turn his attention to the critical issue, said Amarinder Singh, questioning Kejriwal on the steps taken by his government to tackle the problem.