Delhi AQI Turns 'Severe', City Under Strictest Air Pollution Curbs
The GRAP Stage 4 curbs were imposed only hours after GRAP Stage 3 restrictions were put in place in Delhi as AQI worsened during the day.

Strictest winter air pollution curbs were imposed in Delhi on Monday as the national capital's air quality deteriorated to 'severe' due to unfavourable weather conditions. Stage 4 restrictions under Graded Response Action Plan were put in place across the region, mandating a ban on all construction activities and a ban on the entry of diesel-run trucks carrying non-essential goods into Delhi.
Commission for Air Quality Management enforces restrictions under GRAP in Delhi during winter, which categorises air quality 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 Plus, AQI above 450).
The curbs were put in place after Delhi's 24-hour average Air Quality Index (AQI) breached the 400-mark around 10:00 p.m., worsening from 379 at 4:00 p.m. Extremely calm winds and the weather conditions hindering dispersal of pollutants caused the pollutions levels to spike during the day.
GRAP 4 was invoked in Delhi for the first time this season in November after the city and neighbouring regions suffered consistently high pollution levels. The curbs were relaxed in the first week of December on Supreme Court's order after the city's AQI improved.
CAQM took the decision to impose GRAP Stage 4 curbs in Delhi just hours after the implementing GRAP Stage 3 restrictive measures, after the city's AQI breached the 350 mark in the afternoon.
School classes, except for Classes X and XII, have been shifted to hybrid mode under the GRAP Stage 4 restrictions. The restrictions apply to all schools in Delhi, Gurugram, Faridabad, Ghaziabad and Gautam Buddh Nagar.
All construction and demolition activities are also banned under GRAP Stage 4, including public projects like highways, flyovers, power lines, and pipelines.
Public, municipal, and private offices in the region can have only half of their staff working from offices, with the remaining employees have to work from home. States may consider additional measures like closing colleges, non-essential businesses and implementing odd-even vehicle restrictions.
Unfavourable meteorological conditions combined with vehicle emissions, paddy-straw burning, firecrackers and other local pollution sources lead to hazardous air quality levels in Delhi-NCR during winters.
Prolonged exposure to high pollution levels can exacerbate respiratory issues such as asthma, bronchitis and chronic obstructive pulmonary disease and significantly increase the risk of cardiovascular diseases, according to doctors.
(With PTI inputs)