Characterizing the polycentricity in waste governance: a comparative study on Shanghai, Tokyo, and Hong Kong

The mismanagement of waste is jeopardizing urban sustainability. Although polycentric waste governance (PWG) has been introduced, characterizing the PWG remains challenging. This paper employs game theory to illustrate polycentricity by investigating the equilibrium state from the stakeholders' perspective. Shanghai, Tokyo, and Hong Kong are selected as target cities for comparative analysis. The findings reveal the heterogeneous characteristics in three megacities' PWG-the collaboration by principal stakeholders (formal recyclers, informal recyclers, households) in Shanghai, the exclusion of informal recyclers in Tokyo, and the limited contribution provided by the formal recyclers in Hong Kong. The divergent PWG characteristics can be attributed to variations in governance patterns, socioeconomic factors, and policy formulation. Regarding urban sustainability, Tokyo and Shanghai's PWG contribute to the circular economy's expansion, while Hong Kong' potential, in this regard, is undervalued. Despite Tokyo's improved social recognition to practitioners, this PWG mode, primarily driven by formal recyclers and households, presents limited inclusion of low-income groups. Additionally, it is crucial for the authorities in Shanghai and Hong Kong to acknowledge the potential pollution of informal recyclers' non-environmental behavior. This paper offers a valuable model for characterizing and analyzing PWG across different cities, facilitating knowledge aggregation and the implementation of PWG practice.