Institutional Isomorphism and Strategic Response: Evolution Mechanism of Urban Green Infrastructure Labels in the Yangtze River Delta Region from 2005 to 2025

This study examines urban green infrastructure (UGI) branding as a governance practice shaped by institutional homogenization and strategic responses within China’s multi-level policy framework. Against the backdrop of global sustainability agendas, UGI branding is conceptualized as a policy-oriented, symbolically embedded instrument for communicating cities’ commitments to green development and climate resilience. Using an institutional "identity-label-image" framework, integrated with policy diffusion theory and multi-center regional development models, we systematically analyze historical brand-label data from 27 core cities in the Yangtze River Delta. Our findings reveal three key patterns: (1) brand diffusion follows dual pathways of mandatory and imitative homogenization, with evolutionary rhythms tied to five-year planning cycles, generating discernible "policy waves"; (2) within polycentric regional structures, core cities act as institutional "interpreters" and benchmarks, while peripheral cities pursue imitation-driven differentiation, reflecting complex dynamics of collaboration and competition; and (3) urban identities expressed through brand labels progressively align with substantive sustainability transitions, aiming to enhance regional competitiveness and upward recognition. We conclude that UGI branding constitutes a deep-seated mechanism of sustainable urban governance, offering a novel theoretical lens on China’s institutional logic of city branding and providing actionable insights for optimizing collaborative brand governance and integrated green infrastructure planning in urban agglomerations.