Delhi reimposes Grap IV restrictions as air quality plunges to 'severe'

Delhi’s air quality deteriorated sharply on Saturday evening, prompting authorities to enforce the strictest pollution curbs under Stage IV of the Graded Response Action Plan (Grap) after the city’s Air Quality Index (AQI) climbed to a hazardous 428.

 

The decision was taken as a preventive step to stop air quality from worsening further.

 

According to data released by the Commission for Air Quality Management (CAQM), the city’s 24-hour average AQI stood at 400 at 4 pm, with PM2.5 identified as the dominant pollutant, based on readings from 39 of 40 monitoring stations. 

“In view of the worsening trend and unfavourable meteorological conditions, the Grap Sub-Committee decided to invoke all measures under Stage IV with immediate effect across the NCR,” CAQM said in its bulletin. 

 

Stage IV restrictions come in addition to the curbs already in force under Stages I, II and III.

AQI spikes from ‘very poor’ to ‘severe’

Delhi’s 24-hour average AQI on Saturday stood at 354, placing it in the “very poor” category. By around 6 pm, pollution levels deteriorated further, with the AQI touching 416 and later rising to 428, entering the “severe” category.

 

Under Grap, air quality is classified as poor (AQI 201–300), very poor (301–400), severe (401–450) and severe-plus (above 450).

Warnings from forecasts and agencies

Earlier in the week, the CAQM’s Grap sub-committee reviewed air quality trends and forecasts issued by the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM).

 

The panel noted a consistent upward trend in pollution levels and warned that unfavourable meteorological conditions, including slow and variable winds, could push air quality into the “severe” category.

 

Following the assessment, authorities had already activated all measures under Stage III of Grap, in addition to those under Stages I and II. A nine-point action plan was rolled out across the NCR, with agencies such as state Pollution Control Boards and the Delhi Pollution Control Committee (DPCC) directed to ensure strict enforcement.

Weather conditions worsen pollution impact

Dense fog covered large parts of the national capital on Saturday morning, sharply reducing visibility and causing delays to several flights at Indira Gandhi International Airport. Passengers were advised to check flight schedules before travelling.

 

Cold wave conditions also persisted, though the minimum temperature showed a marginal improvement at 7 degrees Celsius, compared with 4 degrees Celsius a day earlier. Relative humidity stood at 100 per cent at 9 am, contributing to foggy conditions, while the maximum temperature is expected to remain around 22 degrees Celsius, according to the IMD.

 

As per CAQM’s health advisory, prolonged exposure to “severe” air quality can cause respiratory illness and significantly aggravate conditions in people with heart and lung disease. Residents have been advised to limit outdoor exposure, especially during peak pollution hours.