The Delhi Traffic Police has started cracking down on violators of the Graded Response Action Plan (GRAP) III in the national capital. On the first day of the ban on BS III petrol and BS IV diesel vehicles, around 550 challans were issued with a total fine of over Rs 1 crore. Additionally, 4,855 vehicles were also fined for not having a valid Pollution Under Control Certificate (PUCC). The ban also extends to inter-state buses from NCR cities into Delhi. Traffic police have intensified checking and returned over 300 prohibited vehicles, prosecuting those without PUCC certificates. This comes as the city faces severe air pollution levels and the Delhi government implements restrictions under stage III of the GRAP.