New Delhi: Delhi and its surrounding areas are facing hazardous air quality, forcing schools to move classes online and halting construction activities. On Monday morning, a thick smog reduced visibility across the city and disrupted both flights and train services.

The city’s air quality index (AQI), which measures fine particulate matter (PM2.5) and other pollutants, was more than 30 times above the limit recommended by the World Health Organization. Such pollution levels can pose serious health risks, particularly for children and the elderly.

The deterioration in air quality is linked to a combination of industrial emissions, vehicle exhaust, dropping temperatures, low wind speeds, and seasonal crop stubble burning in neighbouring states. The government’s Safar app reported an average AQI of 471 early on Monday.

India’s pollution watchdog classifies AQI levels of 101–200 as moderate, 201–300 as poor, 301–400 as very poor, and anything above 400 as severe. While government apps cap readings at 500, private and international monitors often record higher values.

Following the spike in pollution since Saturday, India’s Commission for Air Quality Management (CAQM) invoked stage 4 of its graded response action plan (GRAP), stepping up from level III. As a result, older diesel trucks have been barred from entering the city, construction work has been halted, and students up to class 9 and class 11 are attending hybrid or online classes. The Supreme Court has also advised lawyers and litigants to appear virtually for hearings.

“The wind speed has been very low since Friday, leading to a spike in pollution levels. Due to the western disturbance, the AQI might remain in this range on Sunday as well. Wind speed might pick up from Monday again, bringing some respite,” said Mahesh Palawat, vice president at Skymet.

Authorities have urged residents, particularly children and people with heart or respiratory conditions, to stay indoors and wear masks if venturing outside. Prolonged exposure to severe AQI can affect even healthy individuals. Between 2022 and 2024, six state-run hospitals in Delhi recorded over 200,000 cases of acute respiratory illnesses linked to pollution, the federal government told parliament earlier this month.

According to the Air Quality Early Warning System for Delhi, the city’s AQI is expected to remain in the ‘severe’ category on Sunday and may improve to ‘very poor’ by Monday and Tuesday.

In neighbouring NCR cities, air quality also worsened, with Noida recording an AQI of 455 and Greater Noida 442, placing both in the severe+ category.

BI Bureau