Tens of thousands of people gathered in Delhi on Sunday at Ramlila Maidan for a rally by the opposition INDIA bloc, led by Rahul Gandhi’s Congress party, demanding the resignation of India’s chief election commissioner over a controversial revision of voter lists, according to the BBC.

The Special Intensive Revision (SIR) has removed more than 130 million names from India’s draft electoral rolls. Opposition leaders allege the process gives Modi’s ruling Bharatiya Janata Party (BJP) an electoral advantage and have called for the resignation and impeachment of chief election commissioner Gyanesh Kumar; the BJP denies the claims.