New Delhi: Delhi’s brief respite from polluted air came to an end on Sunday as air quality slipped back into the “very poor” category, just two days after strong surface winds had brought a marked improvement, official data showed. Forecasts indicate that pollution levels are likely to remain in the “very poor” range through the middle of the week.
The air quality index (AQI) was recorded at 298 (poor) at 8 am and worsened to 300 by 11 am. By 4 pm, the 24-hour average AQI stood at 307, placing it in the “very poor” category, according to the Central Pollution Control Board’s daily national bulletin. Pollution levels continued to rise through the evening, touching 310 at 7 pm before easing slightly to 304 by 10 pm.
The deterioration followed a short-lived improvement driven by strong surface winds of 15–20 kmph, which had pushed Delhi’s AQI back into the “poor” category on Friday. The 24-hour average AQI was recorded at 236 on Friday evening and 267 on Saturday.
In view of the improved conditions, the Commission for Air Quality Management (CAQM) had lifted Stage-III measures under the Graded Response Action Plan (GRAP) across the National Capital Region on Friday. Despite the return of “very poor” air quality on Sunday, Stage-III restrictions remained revoked, while Stage-I and Stage-II measures continued to be in force.
Under GRAP, Stage-I measures are implemented when AQI exceeds 200, Stage-II when it crosses 300, Stage-III at 400, and Stage-IV, or “severe plus”, at levels above 450. However, last winter, CAQM had lowered the threshold for Stage-III implementation to an AQI of 350.
According to the Air Quality Early Warning System for Delhi, pollution levels are expected to remain elevated in the coming days. “Air quality is likely to be in the ‘very poor’ category from Monday to Wednesday. The outlook for the subsequent six days also indicates ‘very poor’ air quality,” the agency said in its bulletin on Sunday.
The CPCB defines air quality as “moderate” for AQI values between 101 and 200, “poor” between 201 and 300, and “very poor” between 301 and 400. Levels beyond 400 are categorised as “severe”.
Meanwhile, no significant fog was recorded in the Capital on Sunday, despite the India Meteorological Department (IMD) issuing a yellow alert a day earlier for possible moderate to dense fog. The alert was withdrawn later in the day. An IMD official said clear skies are likely to prevail, with shallow fog in most areas and moderate fog in isolated pockets over the next few days.
Flight operations were also affected, with 20 arrivals and 23 departures cancelled at the Indira Gandhi International Airport as of 10 pm on Sunday, officials said.
The minimum temperature on Sunday settled at 7.4°C, around 0.5°C above normal, compared to 8.1°C a day earlier. The IMD has forecast minimum temperatures between 7°C and 9°C on Monday and 8°C to 10°C on Tuesday, with no significant change expected over the next 24 hours. The maximum temperature remained steady at 17.3°C and is likely to range between 17°C and 19°C on Monday.
The IMD has also forecast dense to very dense fog across parts of north India over the next seven days, with cold day conditions expected in some pockets.
