Delhi’s AQI plunges to ‘severe’ after 24 days

New Delhi: The national capital’s air quality plummeted to alarming levels on Tuesday after a gap of 24 days, with the Air Quality Index (AQI) entering the ‘severe’ category. This decline comes despite stringent anti-pollution measures under the Graded Response Action Plan (GRAP), including a ban on construction activities and the entry of trucks into the city.

According to data from the Central Pollution Control Board (CPCB), Delhi’s 24-hour average AQI soared to 433 at 4 pm, up from 379 on Monday. This marked the first instance of severe pollution since November 23, when the AQI stood at 412. Of the 35 monitoring stations across the city, 28 recorded ‘severe’ air quality levels, with several surpassing the ‘severe plus’ threshold of 450.

The spike in pollution has been attributed to a significant drop in wind speeds, which has trapped local pollutants within the city. Experts suggest that Delhi’s AQI is likely to remain in the ‘severe’ category for the next two days unless meteorological conditions improve.

Prominent areas such as Mandir Marg, Jahangirpuri, Nehru Nagar, Patparganj, and ITO recorded AQI levels in the ‘severe’ category. Meanwhile, localities including Anand Vihar, Ashok Vihar, Bawana, CRRI Mathura Road, and Vivek Vihar breached the 450 mark, classifying their air quality as ‘severe plus.’

Under the GRAP, which categorises air quality from Stage I (Poor) to Stage IV (Severe Plus), the Centre’s air quality panel has imposed the strictest restrictions. Stage IV curbs include: a ban on the entry of non-essential diesel trucks into Delhi; prohibition of all construction and demolition activities, including public infrastructure projects like highways and pipelines; mandatory hybrid learning for schools, except for classes 10 and 12; and directions to allow only 50 per cent of employees in public and private offices to work on-site.

Authorities have also intensified checks on vehicular emissions along Delhi’s borders. In an inter-state coordination meeting, Delhi Police and their counterparts in Haryana and Uttar Pradesh discussed strategies to restrict polluting vehicles. Joint police pickets will be deployed at key border areas to monitor vehicles, particularly BS-III petrol and BS-IV diesel vehicles, which are banned from operating within the city.

The primary pollutant driving the AQI into ‘severe’ territory is PM2.5, fine particulate matter that poses severe health risks. At 4 pm, PM2.5 levels were recorded at 252 micrograms per cubic meter—over four times the national safe standard of 60 micrograms and significantly above the World Health Organisation’s recommended limit of 15 micrograms.

Doctors caution that prolonged exposure to such high pollution levels can exacerbate respiratory conditions such as asthma, bronchitis, and chronic obstructive pulmonary disease (COPD). “Breathing Delhi’s current air is equivalent to smoking around 10 cigarettes a day,” warned a pulmonologist at AIIMS. Cardiovascular risks are also heightened due to the ability of PM2.5 to penetrate deep into the bloodstream.

Interestingly, there has been no contribution from stubble burning to Delhi’s pollution levels, as the paddy harvesting season in Punjab and Haryana has concluded. Vehicular emissions remain the dominant source, accounting for 18.8 per cent of PM2.5 pollution, followed by industrial activities and dust.

Meanwhile, Delhi-NCR schools switched to hybrid mode on Tuesday after the re-imposition of Stage 4 anti-pollution measures. Classes for grades VI-IX and XI will be held hybrid, while classes X and XII remain in-person. Many schools plan to shift lower-grade classes online due to poor air quality.