India, Dec. 2 -- A day after a slight improvement, the air quality in the Capital slipped back to the 'very poor' category at 304 on Monday, marking a return to the prolonged pollution spell Delhi has been battling this winter.

Interestingly, Delhi, where its residents have been breathing toxic air for over a month, has seen no GRAP-IV restrictions so far despite the AQI consistently hovering above the 300 mark.

Recently, the Commission for Air Quality Management (CAQM), a panel to monitor air pollution levels in Delhi-NCR, revoked GRAP-III curbs, while restrictions under Stage 1 and 2 have been intensified after the air quality marginally improved last week. On the other hand, the authorities in Mumbai have invoked GRAP IV, and in cert...