New York City mayor Zohran Mamdani (right) is sworn into office by senator Bernie Sanders while Mamdani's wife Rama Duwaji holds a copy of the Quran on the steps of City Hall. Photo: Reuters Democrat Zohran Mamdani became New York City's mayor on Thursday, vowing during a public swearing-in ceremony on the steps of City Hall to enact an aggressive agenda aimed at making the nation's largest city more affordable for working people.