Delhi and the National Capital Region moved into the strictest phase of the Graded Response Action Plan on December 13, 2025, after air quality levels deteriorated sharply and entered the “severe plus” category. Authorities triggered GRAP stage four as pollution readings crossed emergency thresholds, raising concerns about public health and daily life across the region.
According to official data from the Central Pollution Control Board, Delhi average Air Quality Index crossed 430 by late afternoon and continued to rise in the evening. With weather conditions offering little relief, regulators decided immediate action was necessary to prevent further worsening.
What the Graded Response Action Plan is and why it exists
The Graded Response Action Plan, commonly known as GRAP, is a legally mandated framework designed to tackle air pollution in Delhi-NCR in a step-by-step manner. Approved by the Supreme Court in 2016, it requires state governments and local bodies to enforce specific measures as pollution levels increase.
The plan is monitored and implemented by the Commission for Air Quality Management, which evaluates air quality data and meteorological conditions before escalating restrictions. GRAP is structured to respond quickly, especially during winter months when pollution often peaks due to unfavourable weather.
How GRAP stages are linked to air quality levels
GRAP operates through four stages, each tied directly to the Air Quality Index. When AQI levels range between 201 and 300, air quality is classified as poor and the first stage is activated. The second stage applies when AQI rises to between 301 and 400, placing air quality in the very poor category.
Stage three comes into effect when AQI readings reach between 401 and 450, indicating severe pollution. GRAP stage four, the most stringent level, is triggered when AQI crosses 450 and enters the severe plus category, posing serious health risks even to healthy individuals.
Why authorities invoked GRAP stage four now
Officials cited a sustained upward trend in pollution levels combined with stagnant weather conditions as the main reasons for invoking stage four. According to the Press Information Bureau, the decision followed an emergency meeting of the GRAP sub-committee under the Commission for Air Quality Management.
The committee concluded that immediate enforcement of the strictest measures was necessary to prevent air quality from deteriorating further across Delhi and the wider NCR region.
Restrictions and measures under GRAP stage four
Under GRAP-IV, several high-impact restrictions have been enforced. The entry of BS-IV diesel trucks into Delhi has been banned, except for vehicles carrying essential goods or providing critical services. Construction and demolition activities have been halted, including work on roads, flyovers, highways, power transmission lines, pipelines and telecom infrastructure.
Educational institutions have also been affected. Schools have been instructed to conduct classes for students of Classes six to nine and Class eleven in hybrid mode to limit exposure. Offices across public, municipal and private sectors are operating at fifty per cent capacity, with the remaining workforce directed to work from home.
What this means for residents of Delhi-NCR
The activation of GRAP-IV signals a public health emergency, as severe plus air quality can cause breathing difficulties, eye irritation and aggravated respiratory conditions even in people without pre-existing illnesses. Authorities have urged residents to limit outdoor activities and follow advisories until pollution levels improve.
While these measures aim to provide short-term relief, experts continue to stress the need for long-term solutions to address recurring winter pollution in the region.