This study aims to establish the technical and institutional foundations required to create carbon-neutral cities. Despite the implementation of the Carbon Neutrality Framework Act in 2021, clear concepts and institutional standards for transitioning existing cities into carbon-neutral ones remain lacking. To address this gap, this research proposes regulatory easing measures and policy directions to support the transition. The main objectives are to identify essential spatial elements for building carbon-neutral cities, analyze their current adoption status, and propose actionable directions for achieving carbon neutrality through regulatory sandboxes.