Zohran Mamdani has been sworn in as New York City's first Muslim and South Asian mayor, taking office on New Year's Day. His campaign focused on issues like rent, affordability, and corruption, with pledges including a rent freeze and free childcare. Mamdani assumes leadership as the city sees reduced violent crime and increased tourism, providing an opportunity to address welfare objectives. However, he faces challenges from critics labeling his plans as populist and ambitious, and from an adversarial presidential administration.