India, Dec. 14 -- A thick blanket of smog choked Delhi on Sunday, keeping air quality in the 'severe plus' category a day after authorities imposed both stage 3 and stage 4 curbs under the Graded Response Action Plan (GRAP), with the capital's 24-hour average air quality index (AQI) recorded at 460 at 8 am. It was 431 at 4 pm on Saturday.

Forecasts show no immediate relief is in sight, with the AQI set to stay severe throughout Sunday. It may marginally improve to 'very poor' on Monday, the Early Warning System for Delhi (EWS) said.

At 8 am, all 39 active ambient air quality stations were in the 'severe' category, with some stations on the brink of 'maxing out' at 500. These included Rohini (499); Bawana, Jahangirpuri and Vivek Vihar (4...