Amadalavalasa police detained Communist Party of India (CPI) state security Madhu on Wednesday while he was on his way to Polaki to protest against the construction of a thermal power plant there.
Along with Madhu, about 30 other volunteers were also detained by the police and taken to the Burja police station in the district.
Later, CPI supporters organised protest rallies at Chilakapalem as well as Srikakulam, against the arrest of Madhu and his followers and demanded their release.
CPI leaders termed the police action as unethical and suppression of the rights.
