A tunnel, believed to be around a century-old and once used for water channelling, was found during digging work of the Pune Metro on Friday, officials said.
Local historian Mandar Lawate said the 57 metre-long tunnel, located in the Swargate area, is believed to be around 90 years old.
"The tunnel dates back to the British era and was used for channelling the water," he said.
"There was a water body near Swargate and a canal goes through the area. There is a possibility that water used to get channelised through the tunnel and was later pumped into a swimming pool near Swargate," he said.
The tunnel is 12 to 15 feet beneath the surface and is 1.4 meters wide and 3.5 meters high, he added.
An engineer working at the Metro project said the tunnel was found when piling work on the multi-modal hub and metro was in progress.
"The tunnel is closed from both the sides and there is a 1200 mm diameter pipe which is connected to the canal," he said.