NEW DELHI: The capital's air quality reached emergency levels on Tuesday and was the worst in nearly 11 months. With the noxious morning smog thickening amid dipping temperatures, Delhi recorded its first 'severe' air day of the year, prompting the Commission for Air Quality Management (CAQM) to enforce Stage III restrictions under the Graded Response Action Plan (Grap) across NCR.
The city's average AQI on Tuesday stood at 428 on a scale of 0 to 500, the worst since Dec 19 last year, when the index touched 451. The last 'severe' AQI in Delhi was logged on Dec 23, 2024, at 406.
The sharp rise in AQI, from 362 on Monday, followed a night of calm winds and plummeting temperatures that allowed pollutants to accumulate near the surface, creating a dense smog blanket over the region. Visibility dropped to 600 metres at Safdarjung and 700 metres at Palam around 6.30am.
Winds may help improve air quality slightly today Winds started to drop on Monday and were almost calm through the night. We also have dipping temperatures, which led to significant accumulation of pollutants," said Mahesh Palawat, vice-president at Skymet, adding that winds picked up only post noon on Tuesday, touching around 12 km/hr. "As per forecasts, we can expect winds to stay consistent on Wednesday, so there are chances of marginal improvement," he said.
The stage III of Grap implemented on Tuesday would be effective across Delhi, Gurgaon, Faridabad, Ghaziabad, and Gautam Buddh Nagar. It includes a ban on construction and demolition (C&D) activities and restrictions on BS-III petrol and BS-IV diesel four-wheelers, except those used for essential services.
Non-essential diesel-operated medium goods vehicles and BS-IV light commercial vehicles (LCVs) registered outside Delhi are also prohibited from entering the capital till the curbs remain in force.
Delhi's directorate of education directed all schools to conduct classes up to Class V in hybrid mode. The Commission also advised Delhi and NCR govts to stagger office timings for public and municipal employees to cut down vehicular congestion in peak hours. Similar directions were issued to the Centre for offices located in Delhi-NCR.
Most construction activities are banned, which is likely to hit thousands of daily-wage labourers across NCR.
"All implementing agencies shall keep strict vigil and intensify measures of the extant schedule of Grap," said CAQM, directing that all actions under Stage I, II, and III will continue simultaneously.
Although conditions turned sunny in the late morning and visibility improved to around 2,000m, haze persisted through the day. Delhi's minimum temperature fell to 10.2°C at Safdarjung, the lowest this season and about four degrees below normal. It was 10.4°C on Monday. The maximum stood at 27.7°C, two notches below normal. As per IMD's forecast, shallow fog in the early hours and winds up to 20 km/hour may blow on Wednesday, which may aid in slight dispersion of pollutants.
CPCB data at 9am, when stage III was invoked, showed 33 of Delhi's 39 monitoring stations in the 'severe' category. Bawana (463) recorded the worst air, followed by Wazirpur (460).
Among the most polluted areas were Alipur, Bawana, Burari, Chandni Chowk, ITO, and Jahangirpuri, where early-morning PM2.5 levels touched 600 g/m³.
Experts attributed the spike to meteorological inversion, a phenomenon where a layer of warm air traps cooler air - and pollutants - close to the ground. Forecasts by the Centre's Air Quality Early Warning System (EWS) suggest the capital's AQI is likely to improve marginally to 'very poor' on Wednesday and remain at that level till at least Friday.