Delhi's air quality in 'severe' category
New Delhi: The air quality in the national capital was in the "severe" category for the second consecutive day on Thursday.
The city recorded an air quality index (AQI) 428 at 9.46 am, against 408 on Wednesday morning.
Delhi's suburbs -- Ghaziabad (470), Noida (426), Greater Noida (422), Faridabad (398) and Gurgaon (390) -- also breathed extremely polluted air.
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.