How GRAP Comes Into Force as Delhi-NCR Chokes Each Winter

Every winter, as a thick haze settles over Delhi and its neighbouring cities, authorities activate a familiar set of emergency measures known as the Graded Response Action Plan (GRAP). The framework, designed to curb air pollution during peak smog months, often between October and January, dictates what activities are allowed and what are not as the Air Quality Index (AQI) worsens across the region, breaching hazardous levels.

GRAP is implemented across the National Capital Region (NCR), covering Delhi and parts of Haryana, Uttar Pradesh and Rajasthan, and is enforced by the Commission for Air Quality Management (CAQM) on the basis of real-time and forecasted AQI data. GRAP is a tiered emergency response system that links pollution levels to pre-defined actions.

GRAP is divided into four stages: Stage I: Poor (AQI 201–300), Stage II: Very Poor (AQI 301–400), Stage III: Severe (AQI 401–450) and Stage IV: Severe (AQI above 450). Each stage brings progressively stricter curbs, and measures introduced at one stage continue unless explicitly withdrawn. The idea is to act early, based on both forecasts and observed data, to prevent pollution from spiralling into a public health emergency.

Air pollution in Delhi-NCR during winter is shaped by both local and regional sources, with the problem aggravated by the region’s location in the Indo-Gangetic plains, where unfavourable meteorological conditions, low temperature, high humidity and calm winds, trap pollutants close to the ground.

At the local level, emissions from vehicles, construction and road dust, industrial activity and biomass burning form a substantial part of the pollution load. These emissions intensify during winter as cooler weather reduces atmospheric dispersion.

Pollutants from neighbouring districts such as Sonipat, Panipat, Jhajjar and Rohtak frequently travel into Delhi-NCR, adding significantly to overall pollution levels. On the agricultural side, paddy stubble burning, which typically peaks from late September to late November, has in recent years contributed to winter pollution peaks, although government data suggests that burning incidents in Punjab and Haryana declined by over 90 per cent this winter compared with earlier seasons.

GRAP measures were rolled out in mid-October this year after Delhi’s air quality deteriorated sharply within days. CPCB data shows the city’s daily average AQI rose from around 100 on October 9 to over 200 by October 14, entering the ‘poor’ category amid rising traffic, festive activity and unfavourable weather. Authorities invoked GRAP Stage I on October 14.

Under stage 1, agencies intensified dust-control measures at construction sites, including mandatory covering of materials and mechanised road sweeping. Increased water sprinkling on roads and at hotspots to suppress dust, while enforcement teams step up checks on open waste burning and visible industrial emissions. Public advisories are issued urging people to limit outdoor activity, especially vulnerable groups, even as routine economic activity continues largely uninterrupted.

Yet, by October 19, the eve of Diwali, Delhi’s AQI had continued to deteriorate, hovering close to the 300 mark, prompting the CAQM to enforce GRAP Stage II. This came despite a Supreme Court order on October 15 permitting the limited use of green firecrackers, an order that was widely flouted across the capital.

Enforced as air quality slipped into the ‘very poor’ category, GRAP Stage II introduced stronger emission-control measures, including intensified mechanical road sweeping and daily water sprinkling at pollution hotspots, stricter inspections at construction sites, and tighter restrictions on the use of diesel generator sets.

Authorities also increased parking fees to discourage private vehicle use, restricted the entry of inter-state buses not meeting emission norms, and advised staggered office timings in key NCR districts to reduce traffic congestion and emissions.

In the days following Diwali, air quality failed to recover, with AQI levels frequently breaching the ‘very poor’ and ‘severe’ categories, triggering successive rounds of tighter GRAP curbs through November and December.

By early November, pollution intensified further. On November 11, the region’s AQI pushed beyond 400, placing the air quality in the ‘severe’ category and prompting the Commission to enforce Stage III restrictions across the NCR. These curbs included banning all non-essential construction and demolition work, tightening vehicle restrictions and urging schools and offices to shift to online mode to minimise outdoor exposure for vulnerable groups.

As conditions briefly improved, Stage III measures were revoked on November 26, with CAQM allowing the region to continue under Stage I and Stage II actions when AQI values dipped back into the ‘very poor’ range.

However, pollution surged again with the onset of winter stagnation. On December 13, Delhi-NCR’s AQI breached 400 once again, pushing the region back into the severe category and triggering a re-imposition of Stage III restrictions. That same day, as dense smog and poor dispersion continued, AQI briefly crossed the 450 mark, and authorities invoked Stage IV (Severe ) measures to tackle the emergency situation. This marked one of the harshest phases of the winter smog episode.

Stage III curbs significantly disrupt routine economic and social activity: all non-essential construction and demolition work is suspended; BS-III petrol and BS-IV diesel vehicles are barred from Delhi and adjoining NCR districts; and governments encourage 50 per cent work-from-home and staggered office timings while schools shifted to online learning for younger children.

Stage IV adds the most stringent emergency actions, including the “No PUC, No Fuel” rule, under which vehicles without a valid Pollution Under Control certificate are barred from refuelling, a ban on entry for non-Delhi private vehicles below BS-VI emission norms, suspension of construction and mining, and strong advisories against non-essential travel, with exemptions only for essential services, emergency vehicles, electric vehicles and CNG fleets.

In November 2025, CAQM revised the GRAP framework to make it more proactive and flexible, allowing certain actions previously reserved for higher stages, such as work-from-home mandates and traffic restrictions, to be implemented earlier at Stage III, and giving authorities the power to act on forecasted deterioration in air quality, not just on observed AQI breaches.

GRAP remains the region’s primary tool for limiting damage during these months, even as environmental experts argue that long-term structural solutions are essential to achieving consistently cleaner air in Delhi-NCR beyond winter emergency responses.