A large number of fisherfolk from Thikkavankipalem village had gathered outside the unit demanding removal of an NTPC pipeline allegedly releasing factory waste into the sea, thereby affecting their livelihood.
The agitators sought NTPC to either remove the pipeline or provide employment to the community members concerned.
According to police, the CISF jawans guarding the NTPC premises first resorted to lathicharge, however, the angry mob replied with pelting stones at them, following which the CISF jawans fired six rounds in the air to disperse the demonstrators.
A fisherman and a revenue officer (RO) of Mutyalammapalem village were injured during the protest, they said.