Shimla, Sep 13:
At least three labourers were trapped on Sunday when an under-construction tunnel near Bilaspur town in Himachal Pradesh collapsed, police said.
Fire brigade and police have launched an operation to rescue them.
Official sources said the workers were digging the tunnel when a portion caved in due to landslides.
Machines have been deployed to pump oxygen into the tunnel, a police official told IANS over the phone.
The tunnel, which is part of the under-construction four-laning of the Chandigarh-Manali national highway, is located at Kandrour, between Bilaspur and Ghumarwin towns around 100 km from the state capital.