The incident took place yesterday and a complaint was filed under IPC sections 143 (unlawful assembly) and 323 (voluntarily causing hurt) late last night against the unknown attackers, though no arrests have been made so far, they said.
The activist, identified as Romel Sutharia, was assaulted by over a dozen persons, who also snatched his file bearing documents he had obtained through the RTI when he was on his way to the Collector office for a hearing on his complaint to the Governor.
"On November 23 last year, I had written to the Governor on large-scale illegal mining of sand and stone over Tapi river and across the district. Collector called me for hearing yesterday when I was attacked," Sutharia said.
Police said they were trying to obtain the CCTV footage to ascertain the identity of the accused.
"We have registered an FIR against unidentified persons and are investigating the matter. We will obtain footage of CCTV cameras installed in the District Collector building," Vyara Police sub inspector Kantibhai Motavar.