New Delhi (AFP) – Residents in Delhi woke up to a thick layer of smog following celebrations for the Hindu festival of lights, Diwali. The air quality dipped to the “very poor” category early on 13 November, with authorities warning of further air quality deterioration. Delhi regularly ranks among the most polluted major cities on the planet. The city is blanketed in acrid smog at the onset of winter every year. The government has already announced emergency school closures, stopped construction and banned diesel vehicles from entering the megacity in a bid to bring down pollution levels and get rid of the toxic smog.