New Delhi: Thick toxic haze engulfed the national capital on Tuesday, with the air quality index (AQI) dipping to 453 in the "Severe" category, according to the System of Air Quality and Weather Forecasting And Research (SAFAR).

The AQI of Delhi was 416 at 10 a.m., according to the Central Pollution Control Board (CPCB). The AQI of the national capital region was also high with Ghaziabad (445), Noida and Greater Noida (436), Faridabad (404) having a similar experience. Haryana's Panipat (462), Hisar (406) and Jind (439), too, were in the "severe" category.

SAFAR predicts that the air quality will improve towards "very poor" only by Thursday.

"The AQI is likely to deteriorate to 'severe' category for the next two days and improvement towards 'very poor' is predicted only by November 14," the SAFAR said in its forecast.

It said under the influence of a western disturbance, no rainfall is expected in the Delhi region but the sky will be partly cloudy with cool temperature during the next two days which may lead to lowering of boundary layer height and accumulation of pollutants near the surface.

The effective stubble fire counts estimated by SAFAR-integrated multi-satellite methodology were 1,846 on Sunday.

"Stubble plume intrusion is expected to increase and a decrease in surface wind speed over the Delhi region is forecasted for the next two days," the forecast said.

SAFAR has advised people to avoid all physical activity outdoors.

"Give a miss to walk today. If the room has windows, close them. If the air conditioner provides a fresh air intake option, close it. Keep the room clean - don't vacuum. Do wet mopping frequently," it said.

It also advised people to stop any activity level if they experience any unusual coughing, chest discomfort, wheezing, breathing difficulty, or fatigue and consult doctor.

"Masks known as N-95 or P-100 respirators may only help if you go out. Do not rely on dust masks for protection," it added.