Zohran Mamdani has frozen rents for nearly one million apartments in New York City.
On Thursday, a panel voted for the socialist mayor’s proposal to freeze rents on one-year and two-year leases – one of his key campaign promises.
It means rent on more than 40 per cent of all apartments across the Big Apple’s five boroughs will be frozen – a major policy win for the mayor after six months in the role.
He said: “This is a historic victory for New York City tenants.
“I’ll continue working to deliver a more affordable city by building and preserving affordable housing, lowering building operating costs like insurance, and ensuring that tenants know their rights.”

People hug and cry after the rent guidelines board votes to freeze rents for 40 per cent of the city’s apartments – OLGA FEDOROVA/EPA/Shutterstock
The New York rent freeze marked a good end to a great week for 34-year-old Mr Mamdani, who had earlier celebrated the wins of three candidates he endorsed in the state’s congressional primaries – a demonstration of his vote-winning potential.
Winners Darializa Avila Chevalier, Brad Lander and Claire Valdez defeated established Democrats, with campaigns based on ending US support for Israel and introducing higher taxes on the rich.
The success of Mr Mamdani and his chosen candidates demonstrated a split in the Democratic Party, with some establishment figures concerned about the growing wing of progressive, Left-wing members.
They fear centrist voters may be put off in the November midterm elections, which will determine whether the Democrats can win back Congress from Donald Trump’s Republicans and block the president’s agenda.

Mr Mamdani celebrated the win of Ms Chevalier, centre, a congressional primary candidate he had endorsed, on Tuesday – Seth Wenig/AP Photo
Meanwhile, in November, voters in California will consider a proposal to raise taxes on billionaires temporarily.
Gavin Newsom, the California governor, has maintained a strong opposition to a wealth tax in his own state, arguing that it is a temporary fix for an ongoing problem.
Later this year, California voters will consider the proposal to raise taxes on billionaires temporarily after the labour union backing the measure announced on Thursday that it would forge ahead.
There had been pressure from critics to withdraw the proposal to impose a one-time 5 per cent tax on those whose net worth exceeded $1bn (£758m) amid fears it would lead to a wealth exodus.
In an effort to avoid paying the tax, ultra-wealthy individuals such as Sergey Brin, a Google co-founder, have begun moving assets out of the state.
But the Service Employees International Union Healthcare Workers West has agreed to continue pushing the proposal, with Dave Regan, its president, saying: “I am all in on this.”

People celebrate after Mr Mamdani’s rent freeze proposal was approved – OLGA FEDOROVA/Shutterstock
Many Silicon Valley tech moguls have enthusiastically funded campaigns against the wealth tax.
Mr Brin donated $82m to a political committee called Building a Better California, which backed a variety of initiatives designed to blunt the billionaire tax proposal and has raised more than $118m from fewer than a dozen donors.
Brian Brokaw, a political adviser for Mr Newsom who is leading a political committee opposing the tax, said it would “make California’s biggest challenges worse”.
“Driving away the state’s sustainable tax base for a one-time grab is bad policy and an even worse deal for 40 million Californians who will be left holding the bag,” he said.
Under the proposal, the state would spend the money generated from the tax over multiple years.
The non-partisan Legislative Analyst’s Office estimated that the proposal would generate tens of billions of dollars in the first few years, but that income tax revenues would subsequently decline by hundreds of millions of dollars annually.