Delhi's air quality remains 'severe' for the fourth day in a row

Delhi on Friday recorded another "severe" air quality day for the fourth day on the trot, even as authorities predicted a slight improvement in the situation from Saturday onwards.

The city has recorded 22 "severe" air quality days this year so far.

In November, it recorded 11 such days, the highest in the month since the Central Pollution Control Board started maintaining air quality data in 2015.

The city's 24-hour average air quality index read 415 at 4 pm. It was 423 on Thursday, 407 on Wednesday and 402 on Tuesday.

Neighbouring Faridabad (414), Ghaziabad (386), Greater Noida (368), Gurugram (334) and Noida (397) recorded their air quality in the "very poor" to "severe" category.

An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".

According to the Ministry of Earth Sciences' air quality forecast agency SAFAR, low ventilation and high humidity kept the air quality in the severe zone.

The India Meteorological Department (IMD) said the humidity levels oscillated between 51 per cent and 97 per cent.

Weather experts said the slowing down of winds due to a western disturbance affecting northwest India is leading to accumulation of pollutants and high moisture content in the air makes pollutants heavier, making dispersion difficult.

Under the influence of the western disturbance, light rain is likely in the plains in north India between December 26 and December 29 which may improve the air quality a bit.

Meanwhile, Delhi's minimum temperature increased to 6.9 degrees Celsius.

The maximum temperature settled at 22.9 degrees Celsius, a notch above normal.