Nowadays we are facing the emergence of new challenges, especially focused on environmental behavior and climate change and also the effects and impacts of COVID-19 world pandemic - which can restrain the attainment of the desired sustainability. It is, then, mandatory to reply to all of these challenges through the design of specific paths to attain sustainable development in a collective approach, with the involvement and the commitment of the community and performed in an integrated way. Thus, it is proposed a trans-disciplinary research method based on the European Union title recognition - European Green Capital (EGC) -, directly related to the Circular Economy (CE), together with a Data Envelopment Analysis (DEA). This paper highlights sustainable measures and proposes common managerial strategies and policies, that can support the cities/regions' sustainable practices embedding as well as ensure its overall monitoring to measure if the actions implemented through time are adequate and efficient towards attaining CE and sustainable development. Those are based on the analysis of the best practices of the EGC, which can impact on CE, and using DEA. This approach can follow the city/region evolution and be adapted to the EGC evaluation parameters in order to understand the main characteristics that can contribute to improve governance approaches and help to foster CE into all the cities/regions' ecosystem.

This work has been supported by national funds through FCT – Fundação para a Ciência e Tecnologia through project UIDB/04728/2020.