As mercury falls, Delhi AQI hovers near ‘severe’ category

Delhi recorded an Air Quality Index (AQI) of 399 (very poor / just below severe) at 8am on Wednesday as the mercury fell to 4.2° Celsius. 

The city recorded “severe” air quality (400+) on Tuesday for the first time since December 2.

The air quality is expected to remain in a similar range for the next three days, with slight improvement as temperatures rise later this week.

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Very calm winds, low boundary layer height, and very low temperatures are leading to these conditions, the System of Air Quality and Weather Forecasting And Research said.

Safdarjung, Delhi’s base station, recorded a minimum temperature of 4.4°C on Wednesday morning, while it was 4.2°C at the Lodhi Road station, compared to 4°C on Tuesday, as the cold wave continued.

A cold wave is declared when the minimum temperature is 4.5°C or more below normal, or if it falls to 4°C or lower.

The India Meteorological Department (IMD) said the cold wave conditions in the region will abate from Wednesday onwards and the mercury is expected to rise to around 6°-7°C by Thursday because of an active western disturbance.