The state remains central in contemporary environmental politics and policies, although environmental governance increasingly involves neoliberal and non-state mechanisms. Environmental management in China holds features of an ‘environmental state’ and has been undergoing continuous restructuring, manifested by a recent city-regionalism turn. Informed by the theories of eco-state restructuring (ESR) and eco-scalar fix, this paper investigates air pollution management in the Beijing-Tianjin-Hebei Region by tracing the practices of environmental and territorial governance over the past decades. Through the analysis of parameters of the eco-state, this paper conceptualises the air pollution governance in China into three phases, namely pollutants emission control (the 1990s–2005), campaign-style regional governance (2006–2012) and city-regionalism in air quality governance (2013 onwards). We find that the central state plays proactive but different roles in each phase, characterised by state strategic selectivity, adjustments of state apparatus, deployment of a set of policy instruments, and enhanced state capacities for monitoring, control and legitimation. In this context, the city-regional level has become the key scale at which environmental regulations are targeted and the economic and environmental realms are being (re)formed. This state-led eco-scalar fix process to cope with urgent environmental issues explains the underlying rationality of building up the Beijing-Tianjin-Hebei Region as a new national strategic project.