Zohran Mamdani was poised to deliver a stunning upset in New York City’s mayoral primary that pitted youthful enthusiasm against Andrew Cuomo’s billionaire backers, union endorsements and old-guard Democratic support.

Zohran Mamdani, a state assemblyman and democratic socialist, had a commanding lead over former Gov. Andrew M. Cuomo, who conceded in the Democratic primary.

Zohran Mamdani delivered a political earthquake Tuesday in New York City’s Democratic mayoral primary, riding progressive demands for change in a city facing an affordability crisis to the brink of a stunning victory.