Explained: How did Mamdani become the favourite for mayor?
His energetic campaign, with cost-of-living concerns at its heart, has made Zohran Mamdani popular among working-class voters.
He has used social media to engage with a younger demographic, with slickly-produced videos earning him nearly 5 million followers on Instagram and 1.6 million on TikTok.
He has set out his vision of free buses, free childcare, new apartments and a higher minimum wage - paid for by new taxes on the rich.
Likewise, he has also shared plans to hire thousands of new teachers, renegotiate city contracts and freeze rent increases for the city's one million rent-regulated apartments.
Mamdani's campaign has also been helped by controversies plaguing his competitors.
Andrew Cuomo has been trying to make a political comeback from a sexual harassment scandal that saw him resign as governor of New York state in 2021.
His resignation came after a report from the state attorney general concluded that he had sexually harassed at least 11 women. Cuomo has said he did not intentionally mistreat the women but had run afoul of what was considered appropriate workplace conduct.
The 67-year-old refused to back down after losing the Democratic primary to Mamdani, and has become a more likely winner as an independent than Republican candidate Sliwa, owing to New York's largely Democratic-leaning population.
But the other candidates have continued to use the allegations against Cuomo as fuel during their campaigns, including Mamdani, who, in the final mayoral debate, said one of his alleged victims was in the crowd and asked him: "What do you say to the 13 women that you sexually harassed?"
Adding to Mamdani's chances is the fact that the current mayor, Eric Adams, decided to drop out of the race for re-election in September.
Adams, a Democrat and former senior police officer in the NYPD, enjoyed strong ratings from New Yorkers early in his term, but his reputation took a hit after he was charged with taking bribes and illegal campaign contributions from foreign nationals last year. The charges have since been dropped.