Delhi's AQI turns 'very poor' again, mercury crosses 25.8 C in December

The national capital's air quality once again entered the 'very poor' category on Thursday, while the mercury recorded a high of 25.8 degrees Celsius, one notch above the season's average.

Shallow fog and mist are expected in the city in the next five days, a bulletin by the Indian Meteorological Department (IMD) said.

On Thursday, the minimum temperature settled at 9.2 degrees Celsius, according to the weather department. 

The relative humidity was recorded at 72 per cent, it added. The city's 24-hour average air quality index (AQI) on Thursday stood at 320 in the 'very poor' category. 

An AQI between 0-50 is considered 'good', 51-100 'satisfactory', 101-200 'moderate', 201-300 poor', 301-400 'very poor' and 401-500 'severe'. An AQI above 500 falls in the 'severe plus' category.