While the poor air is making people sick and uncomfortable throughout the NCR, it is particularly bad for those who already have asthma and other respiratory conditions. On Thursday, there was heavy smog covering Delhi-NCR as the air quality deteriorated to a 'severe' level. At 8 am, the national capital's Air Quality Index (AQI) was 364 (in the "Very Poor" category), and at 7 am, it was 408 (in the "Severe" category).