A 32-year-old man was allegedly beaten up and his belongings robbed in Kolkata's Topsia area in the early hours of Friday, police said.
Debojyoti Kandari, who works in a factory in the area, was hit by a dagger on the head by three men around 5.30 am while he was walking towards the Park Circus railway station to catch a train to home, they said, adding that he is a resident the South 24 Parganas district.
The men, who are yet to be identified, then snatched his mobile phone and wallet, a senior police officer said.
A bleeding Kandari then went back to his factory, from where his colleagues took him to the Calcutta National Medical College and Hospital, he said.
A case has been registered and investigations are on, police said.