This policy brief elaborates on how G20 countries can support the investment and development of digital infrastructure (smart city technologies and the Internet of Things [IoT]) and appropriate institutions. These instruments will be necessary for the success of the urban nexus. They can also improve local democracies as catalysts for local effective and inclusive governance. This policy brief also proposes a corresponding sustainability framework integrating human-centric digital technologies, urban nexus indicators, and decentralized decision making. It discusses the applicability of such a framework in critical cases, such as the COVID-19 pandemic.