During the winter, air pollution in Delhi and several other north Indian States increases, primarily as a result of weather-related variables and pollutants from burning stubble.
Following the adoption of Stage-I GRAP (Graded Response Action Plan) measures, the air quality improved. The Union government's air quality early warning system for Delhi states that the air quality is anticipated to be in the moderate category until October 10 and in the poor category on October 11.
Following it, the air quality is expected to stay in the "poor" category. In order to stop further deterioration of the air quality, Stage 1 of GRAP was implemented in the National Capital Region (NCR) on October 7, 2023, after Delhi's Air Quality Index (AQI) fell into the "poor" category. A series of urgent actions are performed to lower air pollution under GRAP.