Air breathed by people in the city categorised as ‘severe’ in quality after fireworks contribute to thick smog Your browser doesn't support HTML5 video. Here is a link to the video instead. Air breathed by people in the city categorised as ‘severe’ in quality after fireworks contribute to thick smog Delhi awoke to a thick haze on Tuesday, a day after millions of people celebrated the Hindu festival of Diwali with fireworks, marking the beginning of the pollution season that has become an annual