New Delhi, Dec. 29 -- The Capital remained trapped under a combination of dense fog and high levels of pollution on Sunday, with the forecasts showing no sign of respite for residents. Delhi's air quality index (AQI), which had been slowly deteriorating over the pastthree days, entered the 'severe' category.

While the day started with AQI in the 'very poor' category, with the 24-hour average recorded at 390 at 4 pm, by 9 pm it had crossed 400, registering at 403 at 10 pm. AQI has been trending upwards since upwards since December 25, when strong winds ended a 13-streak of 'very poor' and 'severe air'.

However, with two straight 'poor' days recorded, there has been a steady deterioration in the AQI, with the 4 pm 24-hour average reading ...