Delhi's Air Quality Index Exceeds 350, Raising Concerns Over Stage 3 GRAP Measures

Residents of Delhi are experiencing not only respiratory discomfort due to pollution but also confusion over the absence of Stage 3 measures under the Graded Response Action Plan (GRAP). The Air Quality Index (AQI) in Delhi-NCR surpassed the 350 mark, a threshold set by the Supreme Court last year. As of November 8, the AQI stood at 355, indicating 'very poor' air quality.

The Central Pollution Control Board (CPCB) reported that the 24-hour rolling average peaked at 388. This level of pollution causes breathing difficulties and eye irritation, highlighting the dangers of high PM2.5 levels. Currently, Stage 2 of GRAP is active, having been implemented on October 19 when AQI exceeded 300. Stage 1 was initiated shortly before as AQI crossed 200.

Understanding GRAP Stages

Stage 1 of GRAP is triggered when air quality is 'poor', with AQI between 201 and 300. Restrictions include banning operations at unregistered construction sites and prohibiting open fires. Stage 2 focuses on reducing private vehicle use and enhancing road cleaning efforts. Parking fees have been increased to discourage private transport.

Stage 3 measures would impose stricter bans on older four-wheelers in Delhi-NCR, specifically BS-III petrol and BS-IV diesel vehicles. Restrictions would also apply to certain diesel-operated vehicles registered in Delhi and non-Delhi registered Light Commercial Vehicles (LCVs), except those carrying essential goods.

Why the Threshold Matters

The Supreme Court directed changes to pollution thresholds in December last year, requiring Stage 3 measures once AQI hits 350, down from the previous threshold of 400. Stage 4 measures are now invoked at an AQI of 400 instead of the original threshold of 450. Despite these directives, Stage 3 has not been implemented even though the threshold has been reached.

An official explained that after last year's court suggestion, GRAP measures were made more stringent. Some actions previously under Stage 3 were moved to Stage 2 in a revised classification issued on December 13 last year. These include daily mechanical sweeping and water-sprinkling on roads.

Criticism from Experts

Experts have criticised this approach as passive. Sunil Dahiya from Envirocatalsysts stated that efforts should focus on preventing AQI from reaching critical levels based on forecasts. Dipankar Saha, former head of CPCB's air laboratory, noted that by the time AQI becomes 'severe', residents have already faced significant exposure to pollutants.

The forecast predicts that air quality is likely to reach 'severe' levels soon. If this occurs, GRAP Stage 4 would be activated with even stricter restrictions including stopping truck entry into Delhi except for essential commodities and clean fuel trucks.

In light of these developments, authorities must consider additional emergency measures such as vehicle rationing schemes or allowing offices to operate at reduced capacity while encouraging work-from-home arrangements.