It’s a wintry afternoon, but it doesn’t feel like the usual January cold. Earth movers are droning, trucks are moving fast. When a siren suddenly starts blaring, workers run to safety. The sound of the siren and the reaction of the people is reminiscent of the 2015 Hindi film Detective Byomkesh Bakshi!, set in the Calcutta of 1942-1943, when Japanese bombers used to patrol the night skies during the Second World War.