New Delhi/Gurugram, Jan. 17 -- The Commission for Air Quality Management (CAQM) in NCR on Friday invoked Stage 3 of the Graded Response Action Plan (Grap) amid forecasts suggesting the air quality index (AQI) in the city and surrounding areas will see a further deterioration over the weekend. Delhi's 24-hour average AQI was recorded at 354 ("very poor") on Friday afternoon, worsening from 343 the previous day. Meanwhile, Gurugram's 24-hour average AQI was recorded at 347 ("very poor") on 4pm on Friday, worsening from 318 at the same time the previous day. "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 has taken the call to invoke all actions as envisaged under Stage 3 of Grap . with immediate effect in the entire NCR, as a proactive measure," a CAQM's Friday order stated. Grap has four stages, invoked as precautionary measures to battle air pollution: Stage 1 is invoked when the AQI crosses 200; Stage 2 when it crosses 300; Stage 3 at 400; and Stage 4 at 450. To be sure, this comes after increased public criticism, including protests, as well as scrutiny by the legislature and judiciary in the last two months, which have pressured CAQM to review the implementation of curbs. The invocation of Stage 3 - triggered when the AQI is projected to cross 400 - brings immediate and widespread curbs. A ban on the plying of Bharat Stage-III petrol and BS-IV diesel four-wheelers is now in force in Delhi, Gurugram, Faridabad, Ghaziabad, and Gautam Buddh Nagar. All private construction and demolition activity across the region has been suspended, with exemptions only for essential public projects. Operations of stone crushers and mining activities are also halted. Additionally, schools for students up to Class 5 in Delhi and neighboring districts must shift to hybrid classes. The move comes amid forecasts by the Air Quality Early Warning System (AQEWS) warned that the AQI is expected to deteriorate to the severe category by Saturday. "The air quality is likely to be in the severe category from Saturday to Sunday. The air quality is likely to be in the very poor category on Monday," the AQEWS bulletin said. Meanwhile, Delhi chief minister Rekha Gupta chaired a high-level meeting to finalise a comprehensive, long-term strategy to combat air pollution, with a push on expanding public transport, strengthening last-mile connectivity and tightening enforcement. The centrepiece is a major expansion of Delhi's bus fleet, aiming to reach 14,000 buses by March 2029. The rollout will be phased, targeting 6,000 buses by December 2026, 7,500 a year later, and 10,400 by March 2028. Of these, 500 will be smaller buses intended to improve last-mile connectivity from metro stations. Road dust control will be strengthened through mechanised sweeping, water sprinklers and anti-dust machines, while large-scale road redevelopment and underground utility ducts aim to reduce recurring construction dust. "For the management of construction and demolition waste, an additional 250 debris spots will be created in all wards of Delhi," said environment minister Manjinder Singh Sirsa on Friday. Gurugram, however, saw a slight reprieve from the cold wave conditions that had gripped it for the past five days. The minimum temperature in Gurugram was 4.9degC on Friday - a slight drop from 5.3degC a day prior. The India Meteorological Department (IMD) forecasts that the minimum temperature is likely to hover between 4degC and 6degC through most of next week....