The incident took place on Thursday when a group of people including those arrested were opposing closure of service road near Radisson square.
IMC Additional Commissioner Rohan Saxena went to the spot to make the protestors understand the necessity of closing the road. As heated arguments ensued, a supporter of Ward no 31 corporator Saroj Chouhan, Radhakrishna Jaiswal allegedly slapped him in public, police said.
Later, he escaped from the scene and is still absconding, they said.
However, enraged protestors kept insisting that the road should not be closed as it will lead to problems for those using it for going to their homes, offices and commercial establishments.