At least two people were killed when a portion of a flyover under construction collapsed over taxis and other vehicles in the congested Posta area here on Thursday police and witnesses said. Seven people were rescued from the spot and rushed to the Calcutta Medical College and Hospital. Several others were reported trapped under the debris at the site in the northern part of the metropolis. 'Two bodies have been extricated' a police officer said. Disaster management and trauma care teams joined the rescue and relief operations. So did hundreds of locals. 'There was a sudden thundering noise' as the Vivekananda Flyover came