Delhi’s AQI worsens a day after Grap-3 removed; CAQM maintains status quo
Delhi's air quality worsened to "very poor" after Stage-3 restrictions were lifted, with an AQI of 381, raising concerns over fluctuating pollution measures.
New Delhi
A day after the Commission for Air Quality Management (CAQM) in NCR lifted Stage-3 restrictions of the Graded Response Action Plan (Grap), Delhi’s air quality worsened on Thursday, hitting the upper-end of the “very poor” categorisation. The 24-hour average air quality index (AQI) at 4pm on Thursday was 377, according to the Central Pollution Control Board’s (CPCB’s) daily bulletin. By 8pm, it was 381 (very poor) and rising, with multiple stations in deep red and the “severe” range.
The decision to scale back Grap was taken amid forecasts indicating that air quality would remain “very poor” through the coming days and just a week after the Supreme Court encouraged the commission to take “proactive action” in tightening pollution curbs.
No meeting on Grap was called by the CAQM subcommittee on Thursday either, despite the deterioration, with officials expecting it to improve again on Friday.
“Based on the forecast provided by the IMD and the Indian Institute of Tropical Meteorology, we were told the AQI will worsen marginally on Thursday as wind speeds will drop. However, by Thursday evening and from Friday onwards, winds are forecast to pick up again and so the AQI is not likely to touch 400 and into the severe category,” a CAQM official said, adding they were monitoring the situation closely.
Experts questioned the rationale behind frequently lifting and invoking Grap, based on fluctuating AQI. “There is not much difference between an AQI of 320 and 350. We know conditions in winters are harsh and unpredictable and often unfavourable, meaning the AQI, if improving, is likely to deteriorate again, so the decision to remove Grap based on marginal improvement was illogical,” said IIT Delhi professor Mukesh Khare.
Thursday was the 22nd consecutive day that Delhi recorded an AQI over 300. This is the third longest such streak since 2019, according to CPCB data. The longest streak since 2019 was recorded last year, when 32 consecutive days of 300+ AQI were logged between October 30 and November 30. This included a peak of 494 (severe) AQI on November 18.
The second longest streak of such days since 2019 is 23, logged between December 17, 2018, and January 8, 2019.
With Stage-3 of Grap lifted, private construction and demolition, mining and other allied activities resumed in NCR. A restriction on older BS-3 petrol and BS-4 vehicles from plying in the region was also lifted with immediate effect, among other vehicular restrictions. Other measures lifted included primary classes having to run on hybrid mode, and both government and private offices operating with 50% workforce.
Sunil Dahiya, founder and lead analyst at Envirocatalysts said Grap, in its current form, was incapable of bringing about significant change. “One, we have seen poor implementation of Grap and two, if it is removed without significant improvement, the sources which were banned return and the emission load increases again, leading to deterioration. Right now, we are also seeing unfavourable conditions and thus, removal of Grap is often counterproductive in such scenarios, unless there is significant improvement,” Dahiya said, adding Grap also fails to target key sources, such as industries and thermal power plants in NCR.
Delhi’s minimum temperature on Thursday was 8.3°C, marginally up from a season low of 8°C that was recorded on Wednesday, the lowest minimum recorded in November since 7.3°C on November 29, 2022. The minimum was 9°C on Tuesday and 9.3°C on Monday, India Meteorological Department (IMD) data showed.
Ashwary Tiwari, an amateur weatherman who runs IndiaMetSky, said an approaching, mild western disturbance had begun influencing the Himalayan belt, with another convergence over Rajasthan causing wind speeds to drop. “This led to stagnation. We can expect strong winds particularly from December 1, when the western disturbance departs,” he said.
Winds are expected to be between 5-10 km/hr during the day on Friday, IMD forecasts show.
The maximum on Thursday was 25.7°C, which was around normal. It is forecast to remain between 25-27°C on Friday.
Delhi's air quality worsened to "very poor" levels, with an AQI of 381 reported on Thursday, following the lifting of Stage-3 restrictions under the Graded Response Action Plan. Experts criticized the CAQM for its inconsistent pollution management. The city has experienced over 22 consecutive days of AQI above 300, prompting concerns about the effectiveness of current measures amidst unfavorable winter conditions.