Delhi air quality likely to deteriorate over next 2 days Updated : December 18, 2018 08:29 PM IST However, the agency said the pollutants will over the next two days reach the upper level of the "very poor" zone and then gradually decline. The overall Air Quality Index (AQI) of Delhi at 4 p.m stood at 353 (very poor). Published : December 18, 2018 08:29 PM IST