Yesterday, Siddiqui had pulled out of the Ramleela programme due to opposition by the right-wing activists following which it was cancelled.
"Police has registered a case against 20 Shiv Sena activists, including district chief Mukesh Sharma, for opposing the film star today," Senior Superintendent of Police Deepak Kumar said.
They have been booked under IPC sections 153(a)--promoting enmity between different groups on grounds of religion, race, place of birth, residence, language, and doing acts prejudicial to maintenance of harmony and 505(2)-- statements conducing to public mischief.
The actor was to play Maarich, a rakshasa (demon), because the demon wanted to be killed by the arrows of Ram.
But, the organisers had to cancel the programme after the activists approached them and expressed their displeasure over Nawazuddin's participation.
The District authorities had said police would provide security to Nawazuddin but he decided to pull out of Ramleela.