A large number of youth came out to demonstrate against the alleged violence by police.
As Uttar Pradesh banned large gatherings across the state to check protests planned against the citizenship law, the police chief said there are "other ways of protest like writing letters".
Section 144 or a ban on gatherings of four or more people has been enforced in all of UP. "Section 144 is in force and no permission for any gathering has been given for December 19. Please do not participate. Parents are also requested to counsel their children," said Director General of Police OP Singh in a tweet around midnight on Wednesday.
Speaking to NDTV, the police chief said the step had been taken to ward against attempts to vitiate the atmosphere.
When it was pointed out that the ban went against the democratic right to protest, Mr Singh replied: "There are many ways to protest. The Constitution gives you the right to protest. But you have other democratic means to protest. You can write, issue appeal. Why don't they write letters?"
He said all district police chiefs felt that there was a need to ban crowds.
The Samajwadi Party had announced statewide protests against the Citizenship Amendment Act (CAA) on Thursday. Protests were also planned by some Muslim groups.
Violent protests were reported on Tuesday in Mau district, where clashes erupted between police personnel and protesters.
A day earlier, a large number of youth came out to demonstrate against the alleged violence by police against students in the Jamia Millia Islamia University and Aligarh Muslim University (AMU).
Videos have emerged that show the UP police may have entered hostels, thrashed students and indulged in vandalism at AMU on Sunday night while dealing with a student protest over the citizenship law.
Protests have swept through the country, mainly college campuses, against the law that makes it easier for non-Muslims from Pakistan, Bangladesh and Afghanistan to become citizens of India if they entered the country before 2015. Protesters, including political parties, activists and many students, allege the law discriminates against Muslims and is against secular principles enshrined in the constitution.