Nearly 40 buses are run daily to Kerala from Gandhipuram and Ukkadam bus stands in the city, with passengers shuttling between Palakkad, Thrissur, Guruvayoor and Ernakulam.
Though the authorities decided to run a bus with police escort, no passenger had entered it out of fear the vehicles may be targetted once they enter Kerala.
Buses from Kerala also did not arrive in the city, police said.