New Delhi, Dec 30 : Construction and demolition activities in Delhi-NCR -- except for some categories of projects -- have been banned with immediate effect after the air quality further deteriorated on Friday, officials said. The sub-committee of the Commission for Air Quality Management (CAQM) in a meeting reviewed the air quality scenario in the region as well as the forecasts for Meteorological conditions and air quality index of Delhi on Friday. The sub-committee observed that the air quality has deteriorated over the last few hours and the AQI of Delhi has been recorded as 399 on December 30. As the AQI in Delhi is expected to slip into 'severe' category owing to calm wind and stable atmospheric conditions, and is expected to deteriorate further, the sub-committee said that that all actions as envisaged under Stage Ill of the GRAP - 'severe' air quality (AQI ranging between 401-450), should be implemented with immediate effect. Along with strict ban on construction and demolition activities, the actions under the stage III of the Graded Response Action Plan (GRAP) include intensifying the frequency of mechanised or vacuum-based sweeping of roads, daily water sprinkling along with use of dust suppressants, before peak traffic hours and also intensifying the public transport services. However, "there will be no ban on the construction and demolition activities under the railway services, metro rail services including stations, airports and inter state bus terminals and other national security, defence-related activities of national importance, and health care facilities". /IANS