During the dramatic moments that followed the collapse, residents used their bare hands to try to rescue people pinned under a 100 meters length of metal and cement that came crashing down, Reuters reports. Footage on TV shows civilians, rescue teams and the army, which has deployed on site, trying to help people trapped underneath massive concrete.

Eyewitness Ravindra Kumar Gupta, said two buses carrying more than 100 passengers were trapped. Eight taxis and six auto rickshaws were partly visible in the wreckage. Resident Ramesh Kejriwal told reports “the concrete had been laid last night at this part of the bridge”.

A coordinated rescue operation was slow to get under way, because of the limited access on either side of the flyover due to buildings and heavy traffic.”Most were bleeding profusely. The problem is that nobody is able to drive an ambulance to the spot” said Akhilesh Chaturvedi, a senior police officer.

An infrastructure company IVRCL official was fast to call the collapse “nothing but God’s act”. According KP Rao, “45% of the work was left, one girder missed & second one fell”. He added that they are working in this field for over 27 years, and nothing like this has happened before, also pointing out that Kolkata Metropolitan Development Authority officials oversaw the project. IVRCL's director of operations, A.G.K. Murthy, said the company was not sure of the cause of the disaster. “We did not use any inferior quality material and we will cooperate with the investigators. We are in a state of shock”, Murthy told reporters in Hyderabad where the firm is based.

The overpass has been under construction since 2009 and has missed several deadlines for completion. Elections are also scheduled for next month in West Bengal and Chief Minister Mamata Banerjee, whose party seeks reelection, rushed to the scene. Back in November a newspaper reported that Banerjee was pushing hard so that the overpass would be completed by February, despite safety concerns expressed by project engineers. This disaster could have a political impact on the elections, affecting interim verdict on Prime Minister Narendra Modi's almost two years in power.