Circular Cities: A Systematic Literature Review of Urban Strategies for Sustainable Transitions

The rapid urbanization process is forcing cities to rethink their development models by adopting circular economy strategies that promote resource efficiency, regeneration, and waste reduction. This systematic literature review investigates how circular strategies are being developed and implemented to support the transition toward circular cities. Following the PRISMA guidelines, 77 studies were selected to provide a comprehensive overview of the approaches currently adopted across different urban contexts. This review identifies a four-macro-level framework encompassing urban circularity strategies, architecture and circular constructions, waste management and recycling, and food sustainability, highlighting both their interconnections and specific challenges. Results show that successful circular transitions depend on the integration of digital innovation, participatory governance, and context-sensitive policy frameworks. However, infrastructural gaps, fragmented regulations, and limited citizen engagement continue to hinder progress. Overall, this review highlights the need for integrated strategies that connect environmental, institutional, and social dimensions to foster more circular, resilient, and inclusive urban systems. These findings contribute to the growing understanding of how cities can operationalize circular economy principles to address sustainability challenges and accelerate the transition toward regenerative urban development.