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.

A few months ago, the “no-name” state assemblyman seemed destined to lose to Andrew Cuomo. On election night, he redrew the city’s political maps.

Here are some of the factors that drove Zohran Mamdani to the cusp of a seismic upset, and how they will affect the general election in November.