At AQI of 417, Delhi’s air quality continues to be in ‘severe’ category

Delhi on Saturday morning recorded an Air Quality Index (AQI) of 417 in the lower end of the ‘severe’ category around 10am, similar to the average 24-hour AQI reported a day earlier.

Air quality in Delhi had turned ‘severe’ on Friday after six consecutive days of ‘very poor’ air, with a dip in temperatures and calm winds continuing to adversely impact the capital.

Delhi’s 24-hour average AQI was 415 as per Central Pollution Control Board (CPCB) at 4pm on Friday – an increase from Thursday’s reading of 390 (very poor) at the same time.

If the average AQI for the day remains ‘severe’, it will be Delhi’s tenth severe air day this month, equalling the record of 2016 and behind just 2021 which had 11 ‘severe’ air days.

The 24-hour average AQI, recorded at 4pm every day, was 390 on Thursday, 394 on Wednesday, 365 on Tuesday, and 348 on Monday.

An AQI of 51 to 100 is classified as ‘satisfactory’, between 101 and 200 is classified as ‘moderate’, between 201 and 300 is classified as ‘poor’, between 301 and 400 is classified as ‘very poor’ and over 400 is ‘severe’ by the CPCB.

Forecasts show that with winds predominantly remaining calm over the next 24 hours, Delhi’s AQI should remain severe on Saturday as well, before improving to very poor again on Sunday and Monday.

The India Meteorological Department (IMD) has forecast light rain in Delhi on Monday due to a western disturbance, which should also raise wind speeds up to 12 km/hr on the day – aiding the dispersal of pollutants.

“Winds had stayed almost calm throughout the day on Friday at Safdarjung and they were averaging below 5 km/hr at Palam, picking up to 6 km/hr briefly around 3pm,” said Kuldeep Srivastava, stating that the predominant wind direction was northwesterly, which led to Delhi recording its second consecutive day where the minimum was below 10 degrees Celsius. Delhi’s minimum on Friday was 9.4 degrees – two notches below normal for this time of the season.