Hindustan Times. With Diwali less than a week away, Gurugram’s air quality deteriorated further on Monday, with the air quality index (AQI) reaching 246 at 4pm, its highest reading this pollution season, according. Gurugram's AQI peaked at 246, marking the season's worst, as Stage 2 of GRAP was enforced in Delhi-NCR due to worsening pollution levels.