Indian capital New Delhi gasps under choking smog

India Gate in New Delhi is pictured through a choking smog that has blanketed the capital.

India's capital New Delhi was enveloped in heavy, toxic smog Sunday -- the worst levels in recent years, with flights diverted or delayed as politicians blamed each other for failing to tackle the crisis.

Every winter, the megacity of 20 million people is blanketed by a poisonous smog of car fumes, industrial emissions and smoke from stubble burning at farms in neighbouring states.