No 'good' days for Delhi air in Jan as winter makes pollution worse

Average monthly AQI at 'very poor' category, city eases graded action plan

Delhi’s air was polluted all of January, a crisis made worse since last year due to fog, calm winds and low temperatures.

Average monthly air quality index (AQI) was 311, data from the state-run Central Pollution Control Board (CPCB) showed. AQI was 279 in January 2022.

AQI measures the concentration of poisonous particulate matter PM2.5, which can cause cardiovascular and respiratory diseases such as lung cancer, in a cubic metre of air. An AQI of 0-50 is considered ‘good’, 51-100 ‘satisfactory’, 101-200 'moderate’, 201-300 ‘poor’, 301-400 ‘very poor’, and 401-500 ‘severe’. Above 500 is the ‘severe-plus or emergency’ category.

AQI was 'poor’ for 11 days and very poor’ for 15 days, the most since January 2018. The air was between ‘good and moderate’ for just two days this January. There were three days of 'severe' AQI in January.

The city withdrew Stage II of a Graded Response Action Plan (GRAP) on February 1 after AQI improved to ‘moderate’ levels on January 31.

AQI improved from 207 (‘poor’) on January 30 to 192 (upper-end of ‘moderate’ category) on January 31 and then to 164 (‘moderate’) on February 1, according to the CPCB data.

All actions under Stage I of GRAP remain and are being implemented by agencies in the national capital region to ensure air quality does not deteriorate, said the Commission for Air Quality Management.

Based on earlier decisions of the Sub-Committee on GRAP, actions up to 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.

Delhi NCR air quality is likely to deteriorate marginally but remain largely in the ‘moderate’ category from next week, according to a state bulletin.