Gurgaon: Commuters on the Gurgaon Expressway were stuck for hours on Monday as Delhi Police cracked down on vehicles not following the odd-even rule while entering the national capital, police said. Traffic on the Delhi-Gurgaon Expressway was hit for nearly two hours as police launched a drive against vehicles bearing odd-numbered registration plates on a day when even-numbered cars are allowed to ply in Delhi. Delhi Police's Special Commissioner Muktesh Chander and his colleagues stopped and issued 'challans' (traffic tickets) to car drivers violating the policy near Rajoukri flyover. Most of the fined motorists were from different parts of Rajasthan, Maharashtra, Gujarat and the southern states who said they were not aware of the new policy. "More than 200 motorists were issued tickets for not following the rule," a Delhi Police source said.