New Delhi: Cold wave maintained its grip in north India, with temperatures settling below normal in most parts as fog enveloped the region disrupting air, rail and road traffic. br br Dense fog enveloped the Indira Gandhi International (IGI) airport in Delhi on Sunday night leading to delay in schedule of around 40 flights. br br Around 150 domestic and international flights at the IGI airport had been affected earlier in the day due to fog, causing inconvenience to passengers.