After brief respite, Delhi AQI back in ‘severe’

The brief respite – and that too only in relative terms – that Delhi experienced from “severe” air quality faded away by Friday evening as the Capital’s air deteriorated again, returning to the worst classification of pollution.
On Friday, in fact, saw Delhi saw a steady deterioration in pollution levels, with the Air Quality Index (AQI) plummeting from 374 (“very poor”) at 9am, to 376 at 11am, then 397 at 5pm, 401 (“severe”) at 6pm, and worsening to 414 by 10pm, according to data furnished by the Central Pollution Control Board’s (CPCB).
The day’s official reading, taken at 4pm, was 393 (“very poor”).
According to CPCB data, out of the 39 AQI stations across the city active on Friday, only six stations were in “severe” at 9am, but by 10 pm, all but 26 of 39 stations were in the “severe” zone.
Weather scientists from the India Meteorological department (IMD), however, warned that wind speed in Delhi and its surrounding areas is set to drop in the coming days under the influence of a western disturbance, which would further contribute to the rise in pollution levels.
Mahesh Palawat, vice president at Skymet, said, “A western disturbance has been affecting the northwestern region from Friday and its intensity will increase from Saturday. As a result of this, the wind speed of the northwesterly winds, which had brought the pollution levels down slightly, will go down again.”
“Dissipation of pollutants will not be possible, as a result of which pollution levels might increase over the weekend. A layer of fog will envelope the city again,” Palawat added.
The Air Quality Early Warning System (AQEWS) predicted that air quality would remain in the “very poor” category at least until Monday, with similar levels expected in the subsequent six days.
“The air quality is likely to be in ‘very poor’ category on Saturday to Monday. The outlook for subsequent six days is that the air quality is likely to be in ‘very poor’ category,” AQEWS said in their bulletin on Friday.
Delhi’s temperature, meanwhile, saw a marginal rise on Friday.
The minimum temperature recorded on Friday was 11 degrees Celsius, which coincided with the normal for this season, as compared to 10.2°C recorded a day earlier. The day’s maximum was 27.2°C, one degree above normal. The maximum was 27.2°C a day before.
“Mainly smog condition with wind speed less than eight kmph from the west direction prevailed over the region in the forenoon today,” said an IMD official.
IMD forecasts indicated a potential rise in both maximum and minimum temperatures over the weekend, attributed to the insulating effect of smog and fog.
A shallow fog is expected to persist through Saturday morning and into the night, potentially raising night-time temperatures slightly due to heat retention, IMD scientists said.
“A smog or moderate fog is likely in the morning of Saturday. A shallow fog might persist in the evening and night as well, which will act as an insulation cover. So, the night-time temperature might rise slightly, as heat will not be able to escape,” the IMD official added.
The maximum might touch 28°C on Saturday and the minimum might go up by a degree as well.