Abdul Rehman, a native of Koop village in Rampur district, was arrested on the basis of surveillance.
He was spreading rumours with an objective of creating disturbance, District Magistrate Abhishek Prakash said.
Prakash said that Rehman, who lived in Agastyamuni Ashram area, had purchased a sim card on May 10, which was being used to circulate the mobile messages.
Meanwhile, curfew was relaxed today from 6 am to 6 pm and there was huge rush of people in the markets in the wake of Eid festival tomorrow.
A peace march led by minister of state Bhagwat Sharan Gangwar and DM Abhishek Prakash was also taken out in the city.
On August 11, trouble broke out in Baradari area when two groups clashed after a Janmashtami procession deviated from its fixed route and was stopped by some persons in Jagatpur Panwaria locality leading to heavy brick batting and firing in which three persons, including a mother-son duo were injured.
Later, curfew was clamped in troubled parts of the city.
This is the second time when curfew has been clamped in the city. Earlier curfew was clamped on July 22 following clashes between two groups which claimed four lives and was lifted completely on August 7.