A New York City housing board voted on Thursday to freeze the rents for about one million regulated flats for up to two years, fulfilling a central campaign promise of Mayor Zohran Mamdani only months into his term. The 7-1 vote by the city’s Rent Guidelines Board set increases at zero on both one-year and two-year leases from October. Hundreds of tenants who crowded into a Manhattan museum auditorium cheered and blew whistles at the result.