New Delhi: Delhi still gasps for some fresh air as the Air Quality Index (AQI) is in the 'poor' category. However, it recorded a slight improvement on Sunday (November 24).

The overall AQI still remains 'poor', docking at 239, according to weather forecaster SAFAR. At 9 am on Sunday, the AQI recorded was 253 (poor category) around India Gate. At Chandni Chowk area, the PM 10 levels were at 246 which is again in the 'poor' category while the PM 2.5 levels were at 328 in the 'very poor' category.

The PM 10 levels were slightly better at Lodhi Road, docking in at 135 which falls in the 'moderate' category while the PM 2.5 remained 'poor' at 235.

On Saturday, the AQI was in the 'very poor' category for the third consecutive day. The overall AQI was recorded at 326.

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

During winter each year, most of northern India suffers from a spike in toxicity in the air due to the change in weather patterns and crop residue burning in the neighbouring states of Haryana, Punjab and Uttar Pradesh.