At the protest attended by scores of people in New Delhi, Kavita Krishnan, a social activist, said India was being transformed from a constitutional democracy to a Hindu supremacist state.
Leaders of 13 opposition parties made a joint statement calling for peace and harmony and after the religious clashes.
"We are extremely anguished at the manner in which issues related to food, dress, faith, festivals and language are being deliberately used by sections of the ruling establishment to polarize our society," the leaders said.
