This policy research was conducted at a time when the redevelopment of aging new towns is necessary, particularly as redevelopment and reconstruction policies are increasingly being driven by the private sector. It emphasizes the need for measures to achieve the overarching goal of carbon neutrality. For the early new towns, referred to as aging planned cities, to transition into carbon-neutral cities, it is critical to develop not only technical solutions but also policy alternatives that induce carbon emission reductions throughout the entire lifecycle of buildings.