India, Dec. 20 -- After four days of marginal respite from 'severe' pollution levels, Delhi's Air Quality Index (AQI) once again neared 400-mark as the city woke up enveloped in a thick blanket of fog and chilly temperatures on Saturday.

According to data from the central pollution control board (CPCB), the average AQI in the national capital over the past 24 hours stands at 398, indicating a 'very poor' air quality, with the principal pollutant being PM 2.5. The capital had registered 'severe' AQI for three straight days since December 13.

A dense layer of smog engulfed the city throughout the morning hours on Saturday. According to data from India meteorological department (IMD) the city recorded temperatures as high as 22.2 degrees C...