New Delhi – The national capital’s brief respite from hazardous pollution ended abruptly on Sunday as the Delhi air quality very poor category returned, dashing hopes of sustained improvement. Just two days after strong surface winds had provided temporary relief, pollution levels climbed back to alarming levels, with official forecasts indicating the situation will persist through mid-week.
Sharp Deterioration in Pollution Levels
The Delhi air quality very poor classification was confirmed by data from the Central Pollution Control Board’s daily national bulletin. The air quality index (AQI) stood at 298 (poor) at 8am on Sunday and worsened to 300 (poor) by 11am. By 4pm, the 24-hour average AQI was recorded at 307, officially placing the Delhi air quality very poor category.
The deterioration continued throughout the evening, with the Delhi air quality very poor rating becoming more pronounced as AQI levels reached 310 by 7pm before settling at 304 by 10pm. This progressive worsening throughout the day demonstrated how quickly pollution can accumulate in the capital’s atmosphere.
Brief Window of Improvement Ends
The return of Delhi air quality very poor levels came as a disappointing reversal just two days after strong surface winds of 15-20 kmph had significantly improved air quality. On Friday, Delhi’s 24-hour average AQI was logged at 236 (poor) at 4pm, representing a notable improvement from previous weeks. Saturday’s reading of 267 had maintained the improved trend, offering hope that the Delhi air quality very poor pattern might be broken.
However, these hopes proved short-lived as meteorological conditions changed, allowing pollutants to accumulate once again in the capital’s atmosphere.
GRAP Stage-3 Measures Remain Lifted
The temporary improvement in pollution levels had prompted the Commission for Air Quality Management to revoke stage-3 measures of the Graded Response Action Plan (GRAP) across the National Capital Region with immediate effect on Friday. Despite the return of Delhi air quality very poor conditions on Sunday, stage-3 measures remained lifted, suggesting authorities were monitoring the situation before reimposing stricter controls.
However, stages 1 and 2 of GRAP continued to remain in force, providing baseline pollution control measures across the region. The Delhi air quality very poor return has raised questions about whether stage-3 measures should be reimplemented.
Understanding GRAP Implementation
The Graded Response Action Plan comprises four stages that are implemented based on AQI levels. Stage-1 measures are generally triggered when the AQI crosses 200, while stage-2 measures apply once levels exceed 300. The current Delhi air quality very poor category theoretically falls within the stage-2 range.
Stage 3, categorised as “severe,” is defined at an AQI of 400, while stage 4, or “severe plus,” applies at over 450. However, last winter, CAQM was directed to implement stage 3 measures at a lower threshold of 350, demonstrating flexibility in responding to Delhi air quality very poor and worse conditions.
Forecast Indicates Extended Pollution Period
According to forecasts by the Air Quality Early Warning System for Delhi, the Delhi air quality very poor classification is likely to persist for several days. “The air quality is likely to be in the ‘very poor’ category from Monday to Wednesday. The outlook for the subsequent six days is that the air quality is likely to be in the ‘very poor’ category,” the AQEWS bulletin stated on Sunday.
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This extended forecast of Delhi air quality very poor conditions suggests residents should prepare for prolonged exposure to unhealthy pollution levels, with potential health impacts for vulnerable populations including children, elderly citizens, and those with respiratory conditions.
Air Quality Classification System
The Central Pollution Control Board classifies air quality across different bands to help citizens understand pollution severity. The system categorizes air quality as “moderate” when AQI is between 101 and 200, “poor” between 201 and 300, and “very poor” between 301 and 400. The current Delhi air quality very poor status falls within the 301-400 range, indicating significant health risks.
AQI levels beyond 400 are categorised as “severe,” representing the most dangerous pollution conditions that can affect even healthy individuals.
Weather Conditions and Fog Situation
Despite India Meteorological Department issuing a yellow alert warning of possible moderate to dense fog on Saturday, no significant fog was observed over Delhi on Sunday. The alert was withdrawn earlier in the day. “No alerts have been issued for the upcoming days. Mainly clear skies will persist, with possibility of shallow fog in most places and moderate fog in isolated parts of the city,” an IMD official stated.
The absence of dense fog, while positive for visibility, does little to alleviate the Delhi air quality very poor conditions caused by pollutant accumulation.
Temperature and Aviation Impact
The minimum temperature on Sunday was 7.4°C, 0.5°C above normal, compared to 8.1°C a day earlier. IMD forecasts show minimum temperatures of 7-9°C on Monday and 8-10°C on Tuesday, with no significant change expected in the next 24 hours. The maximum temperature stood at 17.3°C, unchanged from Saturday.
Aviation operations felt the impact of weather conditions, with 20 arrivals and 23 departures cancelled at Indira Gandhi International Airport as of 10pm on Sunday, though these cancellations were primarily due to fog rather than the Delhi air quality very poor situation.
Regional Fog Forecast
The India Meteorological Department has forecast dense to very dense fog conditions across North India for the next seven days, with cold day conditions likely in some pockets. While fog can temporarily trap pollutants and worsen the Delhi air quality very poor status, it primarily affects visibility rather than being a direct cause of pollution.
Conclusion
The return of Delhi air quality very poor conditions serves as a stark reminder that the capital’s pollution crisis remains an ongoing challenge requiring sustained intervention. As forecasts predict continued poor air quality through mid-week and beyond, residents must take appropriate precautions while authorities monitor whether stricter GRAP measures need reimplementation.
