Lawmakers voted last month to abolish direct mayoral elections in the city 1,500 kilometres (900 miles) east of Moscow, proposing instead that mayors be chosen by local lawmakers from a shortlist drawn up by a special commission.
“I don’t want to be part of this and I am resigning,” Roizman told lawmakers in the local legislature.
Roizman, a charismatic opposition politician who narrowly beat a Kremlin-backed candidate in the mayoral race in 2013, had been due as chairman of the legislature to put the scrapping of elections to lawmakers for a final vote on Tuesday.
Instead, he told lawmakers he refused to “legitimise someone else’s decision” and pronounced the session closed, video of his speech shared online showed.
Roizman has been a vocal critic of President Vladimir Putin and the pro-Kremlin governor of the Sverdlovsk region, in which Yekaterinburg lies.
As mayor, Roizman has regularly attended demonstrations organized by opposition leader Alexei Navalny who was barred from running in a March presidential election, when Putin won a fresh six-year term.
Leonid Volkov, an opposition politician from Yekaterinburg, said Roizman’s resignation had obstructed the passage of the election legislation, but that it was unlikely to stop direct elections being scrapped eventually.
“This political act and civic deed will, however, remain in history,” Volkov wrote on social media.
The idea of scrapping direct elections was proposed by Sverdlovsk Oblast governor Yevgeny Kuivashev. His allies had argued that doing away with elections would save money and streamline decision-making.
Last month, just under 2,000 people demonstrated against the proposal, demanding direct elections be kept and that the governor resign.
Yekaterinburg is a city of 1.4 million in the industrial belt of the Ural Mountains.
Roizman was one of a handful of Kremlin critics who won mayoral posts following a series of major opposition demonstrations as Putin campaigned for office in 2012.
Another of these opposition politicians was Yevgeny Urlashov, who became mayor of Yaroslavl in 2012. He was arrested in 2013 and jailed for 12 and a half years for corruption. Urlashov said he had been framed.