Delhi’s Air Quality Index (AQI) slipped into the “poor category” at 4 p.m. on Friday, following which Stage 1 of the Graded Response Action Plan (GRAP) was imposed in the National Capital Region (NCR) to prevent further deterioration of air quality. The GRAP is a set of emergency measures taken to reduce air pollution. The GRAP’s Stage 1 has a 27-point action plan, which includes sprinkling water on roads, using anti-smog guns, and ensuring proper disposal of construction and demolition waste. It also imposes a ban on the use of coal and firewood in hotels, restaurants, and open eateries. It also mandates the suspension of work at private construction and demolition projects of 500 sq m or more not registered on the portal of the respective State government for remote monitoring of dust mitigation measures. A reading between zero and 50 on the AQI is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, and 401 and 500 ‘severe’. The Committee for Air Quality Management, a statutory body responsible for proactively implementing the GRAP, said various agencies responsible for implementing the action plan have been directed to ensure strict implementation of the pollution control measures. The subsequent stages of the GRAP include various measures, such as increasing parking fees to discourage private transport and enhancing bus and metro services; prohibiting BS III petrol and BS IV diesel four-wheelers from operating in Delhi, Gurugram, Faridabad, Ghaziabad, and Gautam Buddh Nagar.