Sources in Air India said that the AI call centre, located at Udyog Vihar in Gurgaon, received an e-mail on Sunday threatening that the International airport would be blown up on January 12. Though sources in the Air India said that it was a non specific threat, the police have tightened security in and around the international airport as a precautionary measure. The Gurgaon police have instituted a team from the Cyber Crime Department to investigate the origin of the e-mail.