Delhi's air quality had turned 'very poor' on Sunday for the first time since May, mainly due to a drop in temperature and wind speed, which allowed pollutants to accumulate. The quality of air in the national capital continued to remain in the poor category on Friday with the Air Quality Index (AQI) setting at 249, according to SAFAR India.
The city's average air quality index (AQI) stood at 256 at 9 am. Several areas recorded their AQI in the 'very poor' category. Delhi's 24-hour average AQI was 256 at 4 pm on Thursday, 243 on Wednesday and 220 on Tuesday.
According to the Centre's Air Quality Early Warning System for Delhi, the city's air quality is likely to deteriorate to 'very poor' category on Saturday. A 2019 study conducted by the Central Road Research Institute showed that keeping engines running at traffic signals can increase pollution levels by more than 9 percent.
A range of emission inventory and source apportionment studies carried out for Delhi in the past few years suggested that on-road vehicular exhaust emissions account for 9 per cent to 38 per cent of PM2.5 emissions in the capital.
The AQI was a little better as compared to the previous day when it had settled at 256. While Noida recorded an AQI of 269 (poor), Gurugram was at 176 (moderate). Meanwhile, an anti-air pollution drive was launched yesterday (October 26) to keep the pollution in check in Delhi and neighbouring regions.
As stubble burning continues in parts of Punjab and Haryana, air quality in the national capital has worsened in the past few days. According to data, over 2,500 cases of stubble burning have been reported this year so far.
However, farm fire numbers are better than those of the previous two years. The second phase of the Graded Response Action Plan (GRAP) was implemented in Delhi to reduce the effect of increased pollution.
Each of these categories is decided based on the ambient concentration values of air pollutants and their likely health impacts (known as health breakpoints). According to the AQI scale, the air quality check between 0 and 50 is "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 450 "severe".
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