POLLUTION

Delhi Pollution: Thanks to Warm and Windy Weather, February 2023 Was the Capital’s Second Purest Since 2016

File photo
(Piyal Bhattacharjee/TOI, BCCL, Delhi)

Owing to its local meteorological conditions, February 2023 was Delhi’s second cleanest February in terms of air quality since the air quality index (AQI) was introduced back in April 2015. The average AQI through the month amounted to 237, not too far from the lowest February average of 225 recorded last year.

Looking back, the highest average AQI in February was recorded in 2016 at 291, as per CPCB data. It was followed by an AQI of 267 in 2017, 243 in 2018, 242 in 2019, 241 in 2020, 288 in 2021, and then 225 in 2022.

As for February 2023, the month saw five "very poor", 13 "poor", and 10 "moderate" AQI days. However, no "good" or "satisfactory" air days were observed at all this February, meaning the capital still has a large room for improvement as far as the pollution problem is concerned.

For reference, an AQI between 0 and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".

According to experts, the comparatively lower levels of air pollution last month were down to the early departure of winter, followed by the persistence of favourable meteorological conditions thereafter.

The first half of the month remained windy, and those strong breezes were vital in improving the ventilation inside the landlocked capital and aiding the dispersion of pollutants.

In the latter half, high temperatures — the mercury rose four to nine degrees above normal on most days! — freed the trapped pollutants, with the convection phenomenon moving the pollutants from the ground to higher altitudes.

These (comparatively) low pollution levels have since bled into March as well. In fact, thanks to these recent improvements in air quality, pollution control authorities have revoked the curbs enforced in Delhi-NCR under Stage II of the Graded Response Action Plan (GRAP).

From here on, only actions envisaged under Stage-I will be implemented by the concerned agencies in the National Capital Region, as per the announcement made on March 1.

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