Four protestors detained over the proposed 11,200-MW-Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh were released from Jully Central Jail near Itanagar on Saturday, nearly a month after their arrest, officials said.

The four, identified as Adum Tayom, Omak Paron, Okut Paloh and Oson Paron, were detained on October 9 under the Arunachal Pradesh Unlawful Activities (Prevention) Act, 2014, they added.