The regulations came in after the World Health Organization last year named New Delhi the world's most polluted city. The city government has announced a number of exemptions to the rules, including politicians, judges, police and prison officials, women and sick people and two-wheelers such as motorbikes and scooters. Police appeared to be keeping a low profile Friday. Except for a handful of major intersections, where police and civil defence volunteers set up checkpoints to watch for wrong-numbered licence plates, there was little official presence on the roads. When cars were pulled over, the result was almost always a warning, not the $30 fine that has been announced.