NEW DELHI, Nov. 24 (Xinhua) -- The air quality in Delhi and its surrounding areas turned hazardous on Monday, with a thick blanket of smog engulfing several areas in the Indian capital city.

According to the Central Pollution Control Board, many areas, particularly in the eastern parts of Delhi and the adjoining areas, witnessed an Air Quality Index (AQI) of around 450, which was considered "severe" in terms of air pollution standards.

Over the past couple of days, the overall air quality has been poor in Delhi and its adjoining areas, causing some people to experience difficulty in breathing. The number of patients suffering from respiratory ailments increased manifold at several government-run hospitals, local media reported.

As a precautionary measure, authorities in Delhi issued health advisories directing the locals not to indulge in outdoor physical activities unless very necessary. ■