Villagers indulged in vandalism and arson and pelted stones on police, and also targetted sub-inspector Suresh Singh and pelted fireballs at him at Vikrama Memorial Inter College, SP, R B Singh said.
Nine policemen, including DySP Ajay Kumar Singh were injured in the incident, he said.
Sources said that on Saturday, Nandini Sharma, a Class 10 student, was not allowed to take the examination at Vikrama Memorial Inter College at Saraibharati village allegedly for not paying money for copying.
An FIR has been lodged against seven persons and hundreds of unidentified people, of which 40 have been arrested, police said.