Delhi’s AQI Falls Below 300-Mark After A Month As Dry Winds Carry Off Pollutants

Delhi’s Air Quality Index (AQI) dropped below 300 on Monday, bringing respite to residents after a month as dry northwesterly winds and ample sunlight aided in the dispersion of pollutants.

The air quality in the national capital has oscillated between “very poor” (AQI between 301-400) and “severe” (over 400) categories for the past 32 days. Delhi’s Air Quality Index (AQI) was recorded at 273 at 8 AM on Monday, marking a slight improvement from 285 at 4 PM on Sunday. Although categorised as ‘Poor,’ it is the best air quality Delhi residents have experienced in the past month.

The city’s air quality was last recorded in the “poor” category on October 29, with an AQI of 268, according to data from the Central Pollution Control Board (CPCB). The air quality slipped from “poor” to the “very poor” category on October 30 and stayed there for 15 consecutive days before deteriorating further into the “severe” category.

On Sunday, out of 38 monitoring stations in the capital, 11 recorded air quality in the “very poor” category, while the remaining 27 recorded it in the “poor” category, according to the Sameer app. The CPCB classifies AQI between 0 and 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”.

The primary pollutant on Sunday was PM2.5. These fine particles pose significant health risks as they can penetrate deep into the lungs and enter the bloodstream, according to a report by news agency PTI.

Mahesh Palawat, vice president of meteorology at Skymet, attributed the improvement in air quality to consistent dry northwesterly winds since Saturday, blowing at approximately 8 km/hr. These winds remained active overnight and increased to 15 km/hr on Sunday, aiding in the dispersion of pollutants.

Furthermore, the absence of dense fog in the region allowed ample sunlight to reach the surface, which helped scatter pollutants and gases as the mixing height stayed relatively high.