NEW DELHI: The Commission for Air Quality Management, Centre’s pollution watchdog, on Tuesday revoked the GRAP-IV restrictions in Delhi-NCR, citing an improvement in air quality.In its order, CAQM stated that measures under Stage 1, 2, and 3 of the revised GRAP will continue to remain in effect.“While GRAP Stage 4 is being revoked, considering the winter season when weather conditions may not always be favourable, and to ensure AQI levels do not deteriorate further, citizens are urged to strictly follow the citizen charter under GRAP Stage 1, 2, and 3,” the order stated.This decision comes just three days after the commission had reimposed the measure. On Saturday, CAQM had brought back GRAP-IV in the region after air quality levels slipped into the ‘severe’ category.The region has been grappling with high pollution levels for several months now.GRAP Stage IV is activated when the Air Quality Index (AQI) crosses 450, entering the ‘severe+’ category. During Stage IV, private vehicles are not completely banned. Restrictions depend mainly on emission standards and fuel type. Vehicles that meet the prescribed norms are allowed to operate, while older vehicles face stricter curbs. Specifically, BS-III petrol and BS-IV diesel vehicles are prohibited from operating in Delhi-NCR at this stage, except those serving essential services.