Bhim Army chief Chandrashekhar Azad was on Sunday detained here while he was on his way to take part in an anti-CAA and NRC event.
The Dalit leader was in the city to address a gathering on Citizenship Amendment Act, National Register of Citizens and National Population Register.
Police said they had not granted permission for the programme to be held.
Azad's detention comes days after he was released from Tihar prison in Delhi following his arrest for allegedly inciting people during an anti-CAA protest.