Police said they are trying to arrest the attackers.
A vigilance inspector working with the Uttar Pradesh Power Corporation was on Sunday reportedly assaulted by the owner and workers of a water plant he had gone to inspect, police said.
Deepak Kumar Srivastava had visited the RO plant at Pandeypur in Uttar Pradesh's Varanasi after getting a complaint that the plant was being run on stolen electricity, they said.
The inspector, who was returning in his jeep, was stopped by the owner and workers of the plant. They then assaulted him and took away his mobile phone before fleeing the spot, police said.
SP (city) Dinesh Kumar Singh and ADM (city) Vinay Singh rushed to the spot along with a large police force.
Police also seized the water plant.
Mr Srivastava filed a complaint in the incident at Cantt police station. Police said they are trying to arrest the attackers.