Delhi wakes up to first ‘poor’ air reading of the season, AQI at 227

The air quality remained in the moderate category for most of October, barring brief improvements on October 12 and 16 following rainfall.

The Capital recorded its first poor air quality reading of the season on Wednesday morning, with the Air Quality Index (AQI) at 227 at 7.05 am, official data showed.

Delhi last recorded poor air quality on July 12 and 13, when the AQI stood at 261 and 246, respectively. (PTI file)

According to the Central Pollution Control Board (CPCB) data analysed by the HT AQI Dashboard, the air quality turned poor overnight into Wednesday. The deterioration followed Dussehra celebrations on Tuesday evening, when effigies were burnt and firecrackers were set off in several parts of the city, adding to emissions from Durga Puja festivities.

The dip also came as NASA’s satellite counted 182 farm fires in Punjab and Haryana in the three days to October 20. The count since October 1 stands at 397, against 523 over the same dates last season. However, the satellite passes over at about 1.30 pm, and most burning now takes place later in the day, so its count falls far short of the real number. A lower count, therefore, does not mean less burning.

According to the CPCB, an AQI of 0-50 is classified as good, 51-100 as satisfactory, 101-200 as moderate, 201-300 as poor, 301-400 as very poor and 401-500 as severe.

Delhi last recorded poor air quality on July 12 and 13, when the AQI stood at 261 and 246, respectively.

CPCB’s hourly AQI for the city stood at 227 at 7 am, up 48 points from 179 in Tuesday’s 4 pm bulletin. It crossed 200, the threshold for the “poor” category, at 2 am and has not dipped in any hour since.

The air quality remained in the moderate category for most of October, barring brief improvements on October 12 and 16 following rainfall. The AQI stood at 187 on October 18, 139 on October 19 and 179 on October 20.

Data from 56 of Delhi’s 59 air quality monitoring stations showed that two stations — Jahangirpuri and Pusa — recorded very poor air quality, with AQI readings of 308 and 314, respectively. At 16 stations, including Anand Vihar, the air quality remained in the moderate category.

The deterioration in air quality is also attributed to falling temperatures and changes in wind speed, which affect the dispersion of pollutants and contribute to their accumulation in the atmosphere.