Tens of thousands of people gathered in India’s capital on Sunday along with dozens of opposition chiefs calling for a free and fair election — and to protest the arrests of several top political leaders, including the chief minister of Delhi.

For the first time since a broad opposition alliance was formed last year, supporters showed up in force to contest alleged political interference by Prime Minister Narendra Modi and his Bharatiya Janata Party. The gathering at one of biggest public grounds in Delhi came less than three weeks before elections in which Modi’s BJP is favored to win again.

"We are here to save the constitution of this country,” said Mehbooba Mufti, the former chief minister of Jammu and Kashmir. "If the people do not awaken today, your vote will have no value.”