Indicators for the Circular City: A Review and a Proposal

The theme of the circular city is currently much debated in the literature as a possible strategy for achieving sustainability in urban areas. However, as a recent development it still has many features in the making, one of the most important being the issue concerning monitoring and the tool through which to achieve it. In the paper, therefore, the “indicator” tool is explored in depth. Metrics represent a fundamental and complex aspect that is foundational to measuring and quantifying the progress of results achieved with respect to the goals set. Currently, most existing indicators are associated with specific aspects of the circular economy; there have been few examples of indicators designed to assess the circularity of an entire city. The paper aims to identify priority themes and describe a set of indicators to be used at the urban level. In the absence of an established reference frame, themes and indicators were identified through a methodology starting with an extensive literature search and careful analysis, including statistical analysis, of the scientific literature as well as international and European strategies on the subject. A particular result of this research is the definition ofa minimum set of indicators common to all cities, which can be applied for comparative purposes.