Delhi's air turns 'very poor' as haze, fog envelop city, visibility drops

A blanket of haze and fog enveloped Delhi on Thursday morning, trapping pollutants and pushing the city's air quality into the "very poor" category after remaining "poor" for the past few days.

According to the Central Pollution Control Board (CPCB), the national capital recorded an Air Quality Index (AQI) of 357, compared to 279 a day earlier. The dip in air quality was accompanied by reduced visibility across several parts of the city, as fog and calm winds trapped pollutants close to the ground.

The Air Quality Early Warning System for Delhi stated that the city's ventilation index — which indicates the atmosphere's ability to disperse pollutants — remained below the favourable level of 6,000 m²/s. Weak winds of less than 10 kmph and thick fog have prevented pollutants from dispersing, resulting in a hazy sky, it stated.

At 7.30 am, the India Meteorological Department (IMD) reported visibility of 1,000 metres in Palam and 800 metres in Safdarjung, both experiencing calm wind conditions. Areas such as Kartavya Path, Anand Vihar, Burari and Akshardham were shrouded in fog during the early morning hours.

Vivek Vihar and Anand Vihar recorded "severe" air quality levels with AQI readings of 415 and 408, respectively. As many as 33 monitoring stations across Delhi reported "very poor" air quality with readings above 300, CPCB data showed.

An AQI between zero and 50 is considered 'good', 51 to 100 'satisfactory', 101 to 200 'moderate', 201 to 300 'poor', 301 to 400 'very poor' and 401 to 500 'severe', according to the CPCB classification.

The minimum temperature settled at 20.1 degrees Celsius, four notches above normal, while the humidity stood at 90 per cent at 8.30 am. The maximum temperature is likely to hover around 30 degrees Celsius, with shallow fog expected during the evening, the IMD said.