A circle inspector and two others were injured in a clash between the police and a mob at Anchangadi on Sunday during the Vattekkad Chandanakkudam festival.
Chavakkad circle inspector K. Sudarsan, who sustained serious facial injuries, was admitted to a private hospital in Chavakkad and then shifted to another in Thrissur city.
Later in the day, he was taken to a private hospital in Kochi.
Kadappuram Shaheer, 24, and Thahir, 19, who sustained injuries in a police lathicharge, were admitted to hospitals in Chavakkad and Chettuva.
The police resorted to lathicharge after they were pelted with stones by a mob.
A few local people had burst crackers in violation of a police directive to conduct the festivities within the stipulated time.
A large brick was hurled at the circle inspector, the police said.