Does inter-city commuting lead to increasing disparity of public service accessibility within Chinese metropolitan areas? A case study of Guangzhou

•Uneven service accessibility caused by expanding commuting zones (CZs) is examined.•Various fine-grained datasets are used to measure accessibility and to delineate CZs.•Decade-long changes of accessibility within/outside city boundaries are identified.•The out-of-city-boundary part of CZs suffer worsening disadvantage in accessibility.•Policies of regional fiscal coordination are recommended to reduce inequality. The metropolitan-wide inequality in public service accessibility caused by administrative fragmentation is a well-researched topic in Western contexts. In China, however, most cities historically encompassed entire metropolitan areas (often represented by commuting zones or CZs) within their administrative boundaries. Recently, the CZs of several large Chinese cities have expanded beyond these boundaries. The out-of-city-boundary portions of these CZs, while functionally integrated with the core cities, remain fiscally separate. This separation creates challenges as these areas face increased public service demands from inter-city commuters without a proportional increase in income tax revenue, highlighting emerging metropolitan-wide inequalities in public service accessibility. This study investigates the growing disparity in public service accessibility within and outside city boundaries in the CZs of large Chinese cities, focusing on Guangzhou as a case study. Cellphone location data are used to delineate the CZs, while fine-grained population data and points-of-interest data for facilities are employed to measure accessibility to hospitals and schools. The findings reveal a worsening disadvantage in public service accessibility for out-of-city-boundary CZs compared to within-city-boundary CZs between 2010 and 2020. These results underscore the need for effective regional governance to address the challenges posed by administrative fragmentation.