Indian capital Delhi gasps under choking smog

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

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.