As AQI slips in Delhi-NCR, GRAP Stage 1 begins: How the anti-pollution scheme works explainer news

The return of winter in North India has once again brought the shadow of poisonous air. According to the Early Warning System (EWS) for Delhi, Delhi’s air quality index (AQI) remained in the ‘poor’ category on Wednesday morning, with the temperature at 5:30 am recorded at 201 with 19 degrees Celsius. Among city locations, Anand Vihar once again recorded the worst air quality, followed by Wazirpur.

The situation in the wider NCR was worse: Noida’s AQI rose from 228 at 5:00 am to 369 at 7:00 am, Ghaziabad hovered around 320-325, and Faridabad rose from 252 to 267, leaving a layer of smog visible over the region.

The worsening trend increased on Tuesday when Delhi’s 24-hour average AQI reached 211, crossing the ‘poor’ category for the first time since June. In response, officials activated Phase I of the Graded Response Action Plan (GRAP), a set of emergency measures aimed at preventing further deterioration in air quality in the National Capital Region.

But what exactly is GRAP, who implements it, and how does this phased system determine when to act?

What is GRAP and why was it created?

The Graded Response Action Plan (GRAP) is a predefined, incremental framework of pollution-control measures, designed to be initiated if Delhi-NCR’s air quality deteriorates. The idea is to respond quickly and proportionately with actions matched to specific levels of pollution to avoid a full public health emergency.

The scheme was first proposed by the Central Pollution Control Board (CPCB) and presented in the Supreme Court in the case MC Mehta vs Union of IndiaIn 2016, the court approved the recommendations. GRAP was officially notified by the Ministry of Environment, Forest and Climate Change (MoEFCC) in 2017, making it the national capital’s first legally enforceable pollution emergency framework.

Initially, the scheme was implemented by the Environment Pollution (Prevention and Control) Authority (EPCA). However, in 2021, this authority was dissolved and replaced by a new statutory body: the Commission for Air Quality Management in NCR and Adjoining Areas (CAQM), which now has exclusive jurisdiction over air pollution matters in Delhi and adjacent areas of Haryana, Punjab, Uttar Pradesh and Rajasthan.

What is CAQM?

The Commission on Air Quality Management (CAQM) is now the sole agency responsible for deciding when and how to implement GRAP. Established under the CAQM Act 2021, it was created to bring better coordination, forecasting and action across multiple states.

The CAQM is chaired by a senior government official (of the rank of Secretary to the Government of India or Chief Secretary of a State) and transfers the powers of the Central and State Pollution Control Boards in the NCR states. It can issue binding directions, impose fines up to Rs 1 crore and jail violators for up to five years.

The Commission relies heavily on real-time air quality data and forecast models provided by the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM) to take decisions. GRAP measures were initially reactive, starting after air quality deteriorated. But starting in 2022, CAQM has made GRAP a preemptive tool, using AQI forecasts to implement controls earlier.

What is AQI, and why does capturing it matter?

Air Quality Index (AQI) is the central benchmark used to operationalize GRAP measures. Introduced by MoEFCC in 2014 under the Swachh Bharat Abhiyan, AQI simplifies public understanding of complex pollution data.

AQI ranges from 0 to 500, with higher values ​​indicating worse air. It includes eight major pollutants: PM10, PM2.5, NO2, SO2, CO, ozone (O3), NH3, and lead (Pb), each measured according to National Ambient Air Quality Standards (NAAQS).

AQI bands are:

• 0–50: good
• 51-100: satisfactory
• 101-200: moderate
• 201-300: bad
• 301-400: very bad
• 401-450: serious
• 451+: serious+

GRAP phases are directly linked to these AQI bands, and each phase mandates specific emergency actions.

What are the stages of GRAP, and what happens at each stage?

GRAP has four stages, which are activated when the AQI crosses the relevant threshold. These actions apply to Delhi and NCR districts of Uttar Pradesh, Haryana, Rajasthan and Punjab.

Stage I – ‘Poor’ air quality (AQI 201-300)

It is activated when pollution first becomes health-relevant, this phase imposes restrictions aimed at prevention and early containment.

Key measures include:

• Ban on garbage burning and garbage burning
• Mandatory dust control on construction sites; Water sprinkling and wind protection measures
• Close inspection of industrial units and emissions
• Increasing use of CNG in public transport and promoting use of metro/bus.
• Black carbon audit for heavy vehicles
• Immediate switch to 100 per cent piped natural gas in power plants within 10 km of Delhi
• Citizens are urged to avoid exertion outside, report violations and use public transportation

Stage II – ‘Very poor’ air quality (AQI 301-400)

As pollution worsens, the goal shifts to further reducing emissions burdens.

Enforcement actions include:

• Ban on diesel generator sets (except essential services)
• Advanced road dust control with mechanical cleaning and frequent spraying
• Parking charges increased to discourage private transport
• Ensuring uninterrupted power supply to avoid polluting backup sources
• Targeted action in pollution hotspots
• Strict control over construction and demolition debris management

This phase encourages citizens to limit the use of private vehicles and stay indoors during peak haze hours.

Stage III – ‘Severe’ air quality (AQI 401-450)

At this point, attention turns to aggressive mitigation.

Mandatory actions:

• Ban on all construction and demolition (except for public infrastructure and essential projects)
• Shutdown of Brick Kilns, Stone Crushers, Hot Mix Plants
• Mining and stone breaking units closed
• Ban on certain categories of diesel vehicles in selected areas
• Possible online classes for young children

Stage III was earlier implemented in January 2025 when the AQI exceeded 350. Once air quality improved, those restrictions were eased.

Stage IV – ‘Severe+’ air quality (AQI > 450)

This is the most extreme level of intervention and is seen as a last resort.

Measures include:

• Complete halt on construction including highways and roads
• Closing of schools or starting online studies across NCR
• Odd-Even Road Rationing Schemes (Based on Vehicle Registration Number)
• Ban on private vehicles running on diesel
• Restrictions on entry of trucks, except those carrying essential goods or clean fuel vehicles.
• Closing of non-essential business activities, subject to the advice of the State Government
• Order to work from home for offices wherever possible

What is the reason behind platform change and who decides it?

The Sub-Committee on GRAP under CAQM holds regular review meetings where it evaluates:

• Real time AQI data from Central Pollution Control Board (CPCB)
• Forecasting models from IITM and IMD
• Field reports on compliance and weather

These scientific assessments determine whether the GRAP steps are enhanced or relaxed. Importantly, once a higher phase is activated, measures from all previous phases remain in effect.

Why was GRAP Stage I implemented on Tuesday?

On 14 October, Delhi’s AQI reached 211, reaching the ‘poor’ zone for the first time since June 11. The main pollutants were PM10 and ground level ozone. The latter is particularly dangerous because it is formed when oxides of nitrogen and volatile organic compounds react in sunlight, which is common in vehicle emissions and industrial activity.

Officials also noted low wind speeds and clear skies, which allows pollutants to accumulate. According to the forecast by the Centre’s Air Quality Early Warning System, ‘poor’ AQI will be recorded for at least six days.

What is the relation of GRAP with stubble burning and Diwali pollution?

GRAP was designed keeping in mind seasonal patterns, especially post-monsoon agricultural burning, winter wind stagnation and Diwali fireworks.

This year, the stubble burning season may start in November instead of the end of October due to delay in rice harvest due to late monsoon rains and floods. According to this, this could mean that Delhi’s air quality around Diwali could be better than in previous years. Indian Express,

Why does GRAP matter?

Despite its limitations, GRAP remains an important emergency toolkit. This allows authorities to act dynamically, increasing or removing restrictions based on predicted AQI trends, rather than waiting for a public health crisis.

The CAQM Citizen Charter, updated every season, outlines dos and don’ts for residents, including limiting personal vehicle use, avoiding outdoor activity during peak hours and reporting pollution violations to the helpline (1800-180-1708).