Sudden deterioration in AQI due dense foggy conditons coupled with calm winds

Delhi’s overall Air Quality Index (AQI) suddenly and unexpectedly spiked and clocked 400 today as per the 4PM AQI Bulletin provided by Central Pollution Control Board (CPCB). In view of significant deterioration in air quality of Delhi-NCR in last 24 hours, the Sub-Committee for invoking actions under the Graded Response Action Plan (GRAP) of the Commission for Air Quality Management in NCR & Adjoining Areas (CAQM) met today to review the situation. During the meeting, the Sub-Committee comprehensively reviewed the air quality scenario in the region as well as the forecasts for meteorological conditions and air quality index of Delhi. While assessing the overall air quality parameters, the Sub-Committee noted that the air quality has suddenly and unexpectedly deteriorated owing to dense foggy conditions without much sunlight and very low temperatures, coupled with calm winds and stable atmospheric conditions over last few hours. Further, there is an increasing trend in the overall AQI of Delhi in the coming days as per the Air Quality forecast of IMD/IITM Therefore, it is considered necessary to re-impose Stage-III of GRAP with immediate effect in the entire NCR in an effort to steer clear of further deterioration of air quality in the region.

Based on earlier decisions of the Sub-Committee on GRAP, actions upto Stage-I and Stage-II of the GRAP are already in force vide orders dated October 5, 2022 and October 19, 2022 respectively. Stage III & Stage IV of the GRAP have also been imposed and thereafter revoked from time to time based on the prevalent air quality scenario in Delhi.

As per the dynamic model and weather/ meteorological forecast, the average air quality of Delhi is likely to deteriorate further tomorrow and the overall AQI is expected stay in the ‘Severe’ category. Therefore, in an effort to prevent further deterioration of air quality in the region, the Sub-Committee has decided that all actions as envisaged under Stage-III of GRAP – ‘Severe’ Air Quality (DELHI AQI ranging between 401-450), be implemented in right earnest by all the agencies concerned, with immediate effect in the entire NCR. This is in addition to the preventive/ restrictive actions already in force under Stage-I and Stage-II of GRAP.