Delhi's Air Quality Improves With First ‘Poor’ Category AQI In A Month, Experts Credit These Factors

The improvement in air quality to consistent dry northwesterly winds blowing at around 8 km/h since Saturday has strengthened overnight, reaching up to 15 km/h on Sunday, dispersed pollutants.

Rashtrapati Bhavan engulfed in a layer of smog, in New Delhi, Sunday, Dec. 1, 2024. The national capital continued to grapple with toxic air as its air quality remained in the 'very poor' category for the eighth consecutive day on Sunday.

Source : PTI

The Air Quality Index (AQI) of Delhi has dipped below 300 for the first time in over a month, as dry northwesterly winds and ample sunlight, helped disperse pollutants. The national capital's air quality has remained between the "very poor" (AQI 301-400) and "severe" (over 400) categories for the past 32 days.

On Sunday, however, the city's 24-hour average AQI was recorded at 285, placing it in the "poor" category. This is a significant improvement from Saturday's AQI of 346 in the "very poor" category. The air quality of the city was last measured in the "poor" category on October 29, with an AQI of 268, according to data from the Central Pollution Control Board (CPCB).

Whereas, on October 30, the air quality slipped to the "very poor" from the "poor" category and remained for 15 consecutive days before declining further into the "severe" category. Out of the 38 monitoring stations in Delhi, 11 reported air quality in the "very poor" category on Sunday, while the remaining 27 recorded "poor" air quality, as per the Sameer app.

The CPCB categorises AQI from 0 to 50 as "good", next 51-100 as "satisfactory", from 101 to 200 as "moderate", between 201 and 300 as "poor", between 301 and 400 as "very poor", and over 400 as "severe".

PM2.5 was identified as the primary pollutant on Sunday, with concentrations recorded at 114 µg/m³ by 6 PM. These fine particles are particularly harmful as they can penetrate deep into the lungs and enter the bloodstream, posing severe health risks.

Vehicular emissions, a significant contributor to Delhi's pollution, are typically updated daily by the Centre's Decision Support System (DSS) for Air Quality Management. However, data for Saturday and Sunday was unavailable as of 4 PM. The most recent data, from Friday, showed that vehicular emissions accounted for 21.6 per cent of Delhi's pollution.

Speed Of North-West Wind Reduces Dense Fog 

The Air Quality Early Warning System for Delhi reported that surface winds on Monday morning are expected to flow predominantly from the northwest at speeds below 4 km/h.

Smog and moderate fog are likely during the morning hours, with wind speeds increasing to under 8 km/h by afternoon before dropping again to below 4 km/h in the evening and night. Smog or shallow fog is expected in the evening, while the day is anticipated to remain clear.

Mahesh Palawat, Vice President of Meteorology at Skymet, attributed the improvement in air quality to consistent dry northwesterly winds blowing at around 8 km/h since Saturday. These winds strengthened overnight, reaching up to 15 km/h on Sunday, effectively dispersing pollutants.

Additionally, the absence of dense fog in the region allowed more sunlight to penetrate, aiding in the scattering of pollutants and gases. The mixing height also remained relatively high, contributing to better air quality.

Delhi recorded a sunny Sunday, with a daytime high of 27°C, slightly above the normal for this time of year, according to the India Meteorological Department (IMD). The fluctuation of humidity remained between 93 per cent and 63 per cent during the day.

The weather department has forecasted moderate fog for Monday, with the maximum and minimum temperatures expected to settle at 27 and 11 degrees Celsius, respectively.