A systemic shift to a regenerative economic model is fundamental to achieving climate neutrality and keeping resource consumption within planetary boundaries. It requires citizen behaviour change and multilevel governance of the transition. Cities and regions have a central role to play in achieving this. In CityLoops, the key partner supporting cities in achieving this systemic shift was Metabolism of Cities, through the development of the circularity assessment methodology at a sector level (for both biomass and construction) and at a city-wide level

At city-wide level, the Urban Circularity Assessment (UCA) is an urban, economy-wide material flow and stock accounting method, which paired with indicators, enables the assessment of material circularity of a municipality or city. The aim of the UCA, developed under the lead of MoC, is to monitor progress toward a Circular Economy (CE) from an economy-wide perspective at the city-level, rather than just at the level of individual products or sectors.

The development of an UCA necessitates a comprehensive approach that takes into account biomass, metals, non-metallic minerals, and fossil energy carriers flows through extraction, imports/exports, processing, use and waste (including collection and treatment) phases. With this information, a consistent mass balance can be performed, in order to establish systematic monitoring of resource utilisation, waste, and recycling across the socio-economic system.

In addition to the Urban Circularity Assessment, CItyLoops has also developed two Sector-wide Circularity Assessments, providing contextual information on the CityLoops cities, and respectively, their construction and biomass sectors. The assessments illustrate how circular these sectors are through circularity indicators and a Sankey diagram, and analyse and interpret the results, presenting the limitations of the data used. Finally, they offer recommendations on how to make these sectors more circular. The assessment was carried out by the cities themselves, in collaboration with MoC, after receiving extensive training on data collection and data processing. More information can also be found in the UCA handbook and SCA handbook.

Finally, MoC also developed a Circularity Hotspot Analysis, a method for cities to identify urban circularity hotspots for four material categories. Through their work with MoC, the CityLoops cities produced a lot of data and gained a lot of valuable insight about the state and progress of the circular economy on their territory. All of these results have been compiled in MoC's Data Hub which serves as a digital library on the state of the circular economy of the CityLoops cities, providing visitors with access to key documents, an overview of the circular context and activites in each city, and data on material flow.