GRAP-4 curbs in NCR lifted after SC order; AQI improves to ‘moderate’

New Delhi: The Supreme Court on Thursday permitted the Commission for Air Quality Management (CAQM) to relax the stringent anti-pollution measures from GRAP-4 to Stage 2 in Delhi-NCR, following a consistent improvement in air quality over the past few days.

Later in the evening, CAQM revoked restrictive pollution control measures under stages 3 and 4 of the anti-pollution control plan for winters. Diesel cars and trucks once sidelined by the restrictions are now back on the roads.

The national capital recorded its cleanest air in December since 2022, with the Air Quality Index (AQI) falling to the “moderate” category at 165. This marks a significant improvement from previous weeks when the city was grappling with severe air pollution.

“We have perused the figures of the AQI from November 18 till December 4. Up to November 30, the levels were consistently above 300, and it is only during the last four days that the levels have come down below 300,” noted the bench of Justices Abhay S Oka and Augustine George Masih.

However, the court maintained cautious oversight, establishing clear thresholds for reimposing stricter measures. “If the commission finds that the AQI goes above 350, Stage 3 measures have to be implemented, and if AQI crosses 400 lifted after SC order; AQI improves to ‘moderate’

on a given day, Stage 4 measures have to be introduced,” the bench directed.

The relaxation brings relief to various sectors previously affected by the stringent restrictions. Under the revised Stage 2 measures, some restrictions remain in place, including a ban on the use of coal and firewood in industries and commercial establishments, including eateries, and restrictions on diesel generator sets except for essential services.

All construction and demolition sites and industrial units which have specific closure orders against them are also not allowed to resume operations.

Additional Solicitor General Aishwarya Bhati, representing the CAQM, attributed the improvement in air quality to meteorological and geographical conditions. “We may aspire to have climate conditions like Finland or other European countries, but due to the geographical conditions at Delhi and Himalaya sitting at the top, the AQI level rises during this time of the year,” she explained to the court.

Recent data from air quality monitoring stations showed encouraging trends. Of the 38 stations in the city, only five reported “poor” air quality on Thursday, while the majority recorded “moderate” levels. The primary pollutants were PM2.5 and PM10, with PM2.5 levels at 59.9 µg/m³ and PM10 levels at 138.7 µg/m³ as of 3 pm on Thursday.

The improvement represents a dramatic shift from late October when the city’s air quality began deteriorating. The situation had reached critical levels in the second half of November, with AQI exceeding 400, before showing improvement with the onset of December due to strong winds.

However, concerns remain about data monitoring and pollution sources. The Decision Support System (DSS), the primary tool for assessing pollution sources in Delhi, has not been updated since Friday due to technical issues. “We are experiencing a technical glitch with the website, but the DSS model is still running,” explained a senior official at the Indian Institute of Tropical Meteorology (IITM).

The last available data from the DSS showed that Delhi’s transport sector contributed between 21 percent and 24.6 percent to the city’s PM2.5 levels, with “other sources” contributing similar amounts.

Senior advocate Aparajita Singh, appointed as amicus curiae, raised concerns about higher pollution levels in specific areas, particularly highlighting the Mundka area of west Delhi. She emphasized the need to curtail open garbage burning to prevent pollution levels from rising again.

The court acknowledged these concerns and stressed the importance of developing protocols to check open garbage burning and implementing solid waste management rules from 2016.

Looking ahead, the bench scheduled further directions for December 12, maintaining its oversight of the situation. The court also addressed the role of court commissioners, stating they would resume inspections at Delhi’s entry points if Stage 3 GRAP measures needed to be reintroduced. Stages 3 and 4 of GRAP entail a ban on the entry of trucks carrying non-essential goods unless they run on CNG, LNG, or BS-VI diesel.

Diesel-powered medium and heavy goods vehicles (BS-IV or lower) are prohibited, except for essential services while non-essential light commercial vehicles from outside Delhi are also restricted under GRAP stages 3 and 4.

All construction and demolition activities, including public infrastructure projects like highways, flyovers, and pipelines, are also banned.

The CPCB classifies AQI levels on a scale where 0-50 is “good,” 51-100 “satisfactory,” 101-200 “moderate,” 201-300 “poor,” 301-400 “very poor,” and above 400 “severe.”