How should we understand the recent rapid spread of eco‐urbanism around the world and its move into the mainstream? This understanding has become increasingly dominated by narratives of the urban sustainability fix, which stresses the logic of capital accumulation. Within the broader structural processes of ecological modernization, such as transitioning to low carbon growth, consideration of—let alone interest in—the diversity of local politics that shapes the practice and forms of contestation of eco‐urbanism has often been relegated to a position of secondary importance. Meanwhile, investigations of the relationship between the growth of climate governance and grassroots environmental activism often ignore space production as an underlying process of political‐economic transformation. Drawing on a detailed case study of the prevalence of zero‐waste neighborhood experiments in many Chinese cities, which have recently become obsessed with low‐carbon growth, this article underscores the potential of grassroots activism to change the nature, dynamics and landscape of eco‐urbanism significantly. On the basis of the intriguing evidence presented here, it calls for a new understanding of eco‐urbanism: one which is more attentive to the diversity, heterogeneity and contextual sensitivity of urban change at the grassroots level.