Stronger winds, higher mercury improve AQI in Delhi

Forecasts by the Early Warning System (EWS), which is also used by CAQM, shows Delhi’s AQI is likely to remain ‘very poor’ till January 14, and may improve further in the next six days

Better wind speed and gradual rise in temperature led to Delhi’s Air Quality Index (AQI) improving by nearly 100 points on Wednesday, returning to the ‘very poor’ category after remaining in the ‘severe’ zone for two consecutive days.

The AQI improved to ‘very poor’ on Wednesday. (AFP)

According to the Central Pollution Control Board’s 4pm national bulletin, Delhi recorded an AQI of 308 on Wednesday compared to 407 the previous day.

The CPCB classifies an AQI between 0-50 as ‘good’, between 51 and 100 as ‘satisfactory’, between 101 and 200 as ‘moderate’, between 201 and 300 as ‘poor’, between 301 and 400 as ‘very poor’ and over 400 as ‘severe’.

Delhi’s air turned ‘severe’ for the first time this year on Monday, when the AQI was recorded at 434. The heavy pollution spell continued into Tuesday, with the AQI initially touching a reading of 450 in the morning before improving slightly to 407 at 4pm.

VK Soni, scientist at IMD and head of CPCB’s air laboratory, said the air quality deteriorated on Monday due to adverse meteorological conditions, which have eased considerably since then. “Delhi currently has good wind speed, whereas on Monday and in the early hours of Tuesday, we saw calm winds. There was fog over Delhi for almost the entire day on Monday, which meant mixing height was as low as 80 metres, keeping pollutants close to the surface. However, with an increase in temperature the mixing height has gone back up again,” he said.

Forecasts by the Early Warning System (EWS), which is also used by CAQM, shows Delhi’s AQI is likely to remain ‘very poor’ till January 14, and may improve further in the next six days.

“Delhi’s air quality has improved, but remained in the lower end of the ‘very poor’ category on January 11, 2023. On January 12 and 13, it will deteriorate marginally but will remain in the ‘very poor’ category, while it will once again improve on January 14, but stay ‘very poor’. Outlook for the subsequent six days shows that the air quality in Delhi is likely to remain between ‘very poor’ and ‘poor’,” said the forecast by EWS.