Dozens of Indian opposition leaders were detained in New Delhi on Monday as they shouted slogans, jumped barricades and marched to the Election Commission in a rare public protest against what they say are electoral malpractices.

India’s opposition parties have held a protest calling for the rollback of a controversial revision of the voter list in one of the country’s poorest states, where key elections are scheduled in November.

India’s opposition accuses the Election Commission of rushing through a mammoth electoral roll revision in the eastern state of Bihar, saying the exercise could render vast numbers of citizens unable to vote. Gandhi last week said the revision of electoral rolls in Bihar is an “institutionalised chori [theft] to deny the poor their right to vote”.