Why GRAP 3 was implemented 3 days after Delhi AQI crossed 300?: SC

Supreme Court questioned the authorities over the delay in enforcing stage 3 of the Graded Response Action Plan (GRAP) despite the rising pollution in Delhi. The court asked the authorities why GRAP 3 was implemented three days after the AQI crossed the 300 mark. "Once it reaches, it has to be invoked...how can you wait for three days," it asked.