New Delhi, Dec 22 : Graded Response Action Plan (GRAP) stage-III has been invoked in Delhi and its peripherals as air quality is likely to dip into "severe" category, owing to unfavourable Meteorological and climate conditions, said the Commission for Air Quality Management (CAQM) on Friday. On Friday, Delhi's average Air Quality Index (AQI) clocked 409 as per the daily AQI Bulletin provided by the Central Pollution Control Board (CPCB). "In wake of a sudden dip in the overall air quality of Delhi since morning on date, the Sub-Committee for operationalization of the Graded Response Action Plan met today. The Sub-Committee while comprehensively reviewing the overall air quality scenario in the region as well as the forecasts for meteorological conditions and air quality index made available by IMD/IITM during the meeting observed that the overall AQI of Delhi since morning is on a steady rise," said the official. At 10.05 a.m., the average AQI for Delhi on date clocked 397, at 12.05 p.m., it reached 398, at 1.05 p.m. it plunged to 400, and after that, above 400. "Unfavourable Meteorological and climatic conditions including fog and hazy conditions along with low wind speed are the major causes for sudden spike in Delhi's daily average AQI," said the official. "Keeping in view the prevailing trend of air quality, and in an effort to prevent further deterioration of air quality in the region, the Sub-Committee today has taken the call to re-invoke all actions as envisaged under Stage-III of GRAP -- 'severe' Air Quality (AQI ranging between 401-450), today with immediate effect in the entire NCR," said the official. "This is in addition to the restrictive actions under Stage-I and Stage-II of GRAP already in force in NCR. Various agencies responsible for implementing measures under GRAP and Pollution Control Boards (PCBs) of NCR and DPCC have also been advised to ensure strict implementation of actions under Stage-III of GRAP in addition to actions under Stage-I and Stage-II of GRAP during this period," said the official. An 8-point action plan as per Stage-III of GRAP is applicable with immediate effect from Friday in the entire NCR. This 8-point action plan includes steps to be implemented/ ensured by different agencies and Pollution Control Boards of NCR and DPCC. The CAQM had directed to further intensify the frequency of mechanised/ vacuum-based sweeping of roads, ensure daily water sprinkling along with dust suppressants, before peak traffic hours, on roads and right of ways including hotspots, heavy traffic corridors and ensure proper disposal of the collected dust in designated sites/ landfills and enforce strict ban on construction and demolition activities in the entire NCR. "For all construction projects in NCR, non'polluting/ non-dust generating activities such as plumbing works, electrical works, carpentry related works and interior furnishing / finishing / decoration works (excluding painting, polishing and varnishing works etc) shall be permitted to be continued," said the CAQM. The CAQM further said to close down operations of stone crushers, all mining and associated activities in NCR. The CAQM also imposed restrictions on plying of BS III petrol and BS IV diesel LMVs (4 wheelers) in Delhi and in the districts of Gurugram, Faridabad, Ghaziabad and Gautam Budh Nagar. /IANS