The Central government’s air quality monitoring panel on Tuesday revoked Stage IV (‘Severe+’) measures under the Graded Response Action Plan (GRAP) in Delhi and the National Capital Region (NCR) following an improvement in air quality. However, actions under Stages I, II, and III will remain in force to prevent any further deterioration of air quality, the Commission for Air Quality Management (CAQM) announced on December 24.The decision comes after Delhi’s Air Quality Index (AQI) improved to 369 (‘Very Poor’) at 4 PM on December 24, down from a peak of 401 (‘Severe’) recorded on December 16.The improvement in air quality was attributed to favourable meteorological conditions, including improved wind speed, according to forecasts from the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM). In line with the Supreme Court’s directives, Stage IV measures were initially invoked when AQI levels breached the 400 mark on December 16.The measures were aimed at curbing severe pollution levels and included restrictions on industrial activities, construction, and entry of non-essential trucks into Delhi.The Graded Response Action Plan (GRAP) is a set of emergency measures implemented in Delhi-NCR to tackle air pollution based on the severity of the Air Quality Index (AQI). The centre’s air quality panel stressed the importance of continued vigilance. “Actions under Stage I, II, and III of the revised GRAP shall remain invoked and be implemented, monitored, and reviewed by all the agencies concerned in the entire NCR to ensure that the AQI levels do not slip further,” the commission said in its order.Citizens were also urged to adhere to guidelines under Stage III. “Keeping in view the winter season, when weather conditions may not always be favorable, and to ensure that AQI levels do not slip further, citizens are requested to strictly adhere to the Citizen Charter under GRAP-III,” the commission added. The CAQM Sub-Committee on GRAP assured that it would continue to monitor air quality and issue appropriate directives as necessary, stating, “The Sub-Committee shall be keeping a close watch on the air quality scenario and review the situation from time to time for further appropriate decisions depending upon the air quality in Delhi and forecasts made by IMD/IITM.”