After season's coldest night, Delhi wakes up to another day with toxic air

New Delhi: Delhi witnessed yet another dawn with a blanket of toxic air on Wednesday, as the capital recorded an Air Quality Index (AQI) of 426 in the "severe" category, which followed the coldest night of the season in the city so far.

The city's minimum temperature dropped to 11.1 degrees Celsius Tuesday night, according to the India Meteorological Department (IMD).

The drop in temperature combined with dense fog has blanketed the city, reducing visibility to 500 metres as of 8.30 am. The IMD has forecast dense fog to persist throughout the day.

Humidity levels stood at 84 per cent in the morning. The maximum temperature for the day is expected to settle at 25 degrees Celsius.

Delhi had an AQI reading of 426 at 9 am on Wednesday, according to the Central Pollution Control Board (CPCB).

An AQI of 400 or higher is classified as "severe," posing health risks to healthy individuals and those with pre-existing medical conditions.

All but one of the 38 monitoring stations in the national capital were in the red zone. The Lodhi Road station was not in the red zone recording an AQI in the "very poor" category.

Delhi's air quality first breached the "severe plus" category on Sunday, leading to the implementation of Stage IV restrictions under the Graded Response Action Plan (GRAP) on Monday morning.

These measures include a complete ban on construction and demolition activities and suspension of physical classes in schools.

The Commission for Air Quality Management (CAQM) also implemented additional restrictions, including a ban on the operation of four-wheeler diesel light motor vehicles (LMVs) in Delhi and NCR districts bordering the capital, except for BS-VI vehicles and those used for essential or emergency services.

Diesel-powered medium and heavy goods vehicles have also been barred from entering Delhi, except those transporting essential goods. Only electric and CNG trucks are permitted, with exceptions for essential services.

First introduced in 2017, GRAP categorizes air quality into four stages based on severity: Stage 1 - "poor" (AQI 201-300), Stage 2 - "very poor" (AQI 301-400), Stage 3 - "severe" (AQI 401-450), and Stage 4 - "severe plus" (AQI above 450).