Thousands joined a protest led by opposition politicians in India’s capital on Sunday, renewing demands for the country’s election chief to resign over an overhaul of voter lists they say unfairly benefits the ruling party.

The nationwide revision of electoral rolls has sparked political disputes and street protests in the world’s largest democracy over the last month.

The Election Commission says the initiative is necessary to ensure accurate voter lists, but the opposition claims it is being manipulated to favour Prime Minister Narendra Modi’s Bharatiya Janata Party (BJP).

Both the Election Commission and the BJP deny the accusations.

On Sunday, protesters led by opposition Congress party leader Rahul Gandhi chanted “vote thief, leave your seat” and beat drums while marching from central parts of New Delhi to Ramlila Maidan, a large outdoor venue.

“I have been a voter since I was 18 and now I find myself struck off the list,” protester Nandita, 46, told AFP, giving only one name.

“It’s important to be here because of the way things are going. The cost of living is going up… The only option is to take to the streets peacefully.”

The Cockroach Janta Party (CJP), an online youth-led protest movement, has also thrown its weight behind the campaign against the voter-roll revision.

The overhaul of India’s voter rolls has resulted in more than 133 million names being removed from electoral lists, according to figures reported by Indian media and cited by opposition parties in court filings.

Critics say the removals have disproportionately affected minorities, particularly Muslims.

Members of Hindu-nationalist BJP have long alleged that large numbers of undocumented Muslim migrants from neighbouring Bangladesh have fraudulently entered India’s electoral rolls.

Election authorities say the revision was intended to eliminate duplicate, deceased and fraudulent entries, and that eligible voters remain entitled to apply for inclusion on the roll.

Human Rights Watch has said the removal of voters was “arbitrary and deeply flawed”.

“The authorities should immediately scrap the voter roll revision process that has denied India’s most marginalised people their right to vote and other government services,” it said in a statement this week.

The Cockroach movement has been heavily involved in the pushback to the voter-roll revision and several of its leaders were temporarily detained by police during protests last month.

The CJP has gained millions of followers on social media since it was launched in May.

Earlier protests organised by the CJP in July over exam irregularities forced the resignation of the education minister, marking a rare climbdown by Modi’s administration.