New Delhi: Delhi woke up on Sunday to a dense blanket of smog, with air pollution levels plunging deeper into the ‘severe’ category across the national capital. Data from the Central Pollution Control Board (CPCB) showed the Air Quality Index (AQI) touching an alarming 462 at 6 am, signaling hazardous conditions even for healthy individuals.
All 40 air quality monitoring stations in the city displayed ‘red’ alerts, confirming that pollution levels had crossed the threshold of severe air quality. Rohini in north-west Delhi recorded the highest AQI at 499, with fine particulate matter (PM2.5) emerging as the dominant pollutant. Jahangirpuri and Vivek Vihar followed closely, each registering AQI readings of 495, reflecting uniformly poor air conditions across residential and commercial zones.
Several parts of the city reported sharply reduced visibility due to the heavy smog. In areas such as Patparganj in east Delhi, where the AQI stood at 488 in the early morning, motorists were seen driving cautiously with headlights switched on even after sunrise, underscoring the extent of atmospheric haze gripping the capital.
The AQI serves as a key public health indicator to communicate the severity of air pollution and associated health risks. It is calculated based on eight major pollutants PM10, PM2.5, ozone, sulphur dioxide, nitrogen dioxide, carbon monoxide, lead, and ammonia. According to CPCB standards, an AQI above 400 falls in the ‘severe’ category, posing serious health threats and prompting advisories against outdoor activities, particularly for children, the elderly, and those with respiratory or cardiac conditions.
Experts note that while India’s AQI scale is capped at 500, pollution levels can effectively go beyond this limit. AQI readings above 500 are still classified as ‘severe’, indicating a public health emergency. Professor Gufran Beig, Chair Professor at the National Institute of Advanced Studies, explained that pollution above AQI 400 is already hazardous, and displaying higher numbers may not significantly change the health advisory but could cause public panic. However, environmental analysts argue that extremely high pollution levels sharply increase immediate health risks, including hospitalisation for vulnerable groups during peak pollution episodes.
In response to the rapidly deteriorating air quality, the Commission for Air Quality Management (CAQM) imposed restrictions under the Graded Response Action Plan (GRAP), initially invoking Stage 3 and subsequently escalating to the most stringent Stage 4. Authorities attributed the sudden spike in pollution primarily to unfavourable meteorological conditions rather than local emissions.
According to CAQM, the approach of a weak Western Disturbance over north-west India led to a sharp drop in wind speed, occasional calm conditions, a shift in wind direction, and increased moisture in the lower atmosphere. These wintertime conditions are ideal for the formation of smog and fog, severely restricting the dispersion of pollutants and trapping them close to the ground.
Under GRAP-4 measures, the entry of non-essential trucks into Delhi has been banned, except for vehicles carrying essential commodities or those operating on cleaner fuels such as CNG, LNG, electricity, or BS-VI diesel. Diesel-powered medium and heavy goods vehicles registered in Delhi that do not meet BS-VI standards have also been barred, with exemptions only for essential services. Construction and demolition activities, including major public infrastructure projects, have been halted to curb dust emissions.
Additionally, state governments across the Delhi-NCR region have been advised to consider shifting physical classes for students of Classes VI to IX and XI to online mode. Offices in the public, municipal, and private sectors have been encouraged to adopt work-from-home arrangements for at least 50 per cent of their workforce, along with staggered office timings, to ease traffic congestion and reduce vehicular emissions.
With pollution levels remaining critically high, authorities have urged residents to limit outdoor exposure, use masks when necessary, and follow health advisories as Delhi continues to grapple with one of its worst air quality episodes of the season.