Delhi’s air quality plummets, Grap 3 and 4 back on

The Commission for Air Quality Management (CAQM) in NCR and adjoining areas said it held a review earlier in the day and noted a rising trend in AQI due to unfavourable meteorology

New Delhi

Delhi’s air quality index crossed into severe level. (Sanjeev Verma/HT Photo)

Stages 3 and 4 of the Graded Response Action Plan (Grap) to combat pollution was enforced in the Capital as air quality index (AQI) plummeted by over 125 points in a 24-hour period, clocking a reading of 386 (“very poor”) at 4pm on Wednesday, according to the Central Pollution Control Board’s (CPCB’s) daily bulletin, and further dipped below the 400 mark at 8pm, clocking “severe” level.

The AQI was 275 (“poor”) at 4pm on Tuesday. Subsequently, on Wednesday, Grap 3 and 4 halted all construction and demolition activities across NCR, invoked a series of vehicular restrictions in the region and restricted in-person classes in schools.

The Commission for Air Quality Management (CAQM) in NCR and adjoining areas said it held a review earlier in the day and noted a rising trend in AQI due to unfavourable meteorological conditions.

“The AQI of Delhi was 275 (poor) on January 14, but has exhibited a sharp increasing trend on January 15, touching 386 by 4pm, owing to dense foggy conditions and low temperatures, leading to extremely low mixing height and ventilation coefficient for dispersion of pollutants,” it said in a statement, adding it was likely to spike further.

“Thus, the CAQM sub-committee has taken the call to straightaway invoke all actions under Stage 3 and Stage 4 measures of Grap with immediate effect in the entire NCR,” the statement said, directing state and central pollution bodies to ensure strict implementation of curbs.

Under the curbs, schools in Delhi-NCR, except for classes 10 and 12, will work on a “hybrid” mode.

Besides, there will also be curbs in Delhi on operations of Delhi-registered diesel-operated medium goods vehicles (MGVs) that are BS-4 and lower, diesel-operated light commercial vehicles (goods carriers), registered outside Delhi and are BS-4 or lower, on entering the Capital. However, vehicles carrying essential commodities or providing essential services are exempted in both cases.

Further, under Stage 3, timings for public offices and municipal bodies across NCR will have staggered timings and the Centre might decide to stagger office timings in Delhi too. Under Stage 4, these offices are required to only function at half-strength.

Other additional measures that can be taken include the closure of schools and colleges by states, and the implementation of the Odd-even road rationing scheme.

The Supreme Court on December 5, 2024, directed CAQM to invoke Grap Stage 3 when the AQI hits 350, against the earlier threshold of 400, and Grap Stage 4 when the AQI crosses 400.