This perspective argues that sustainability-transition research must pay greater attention to smaller cities. These cities accommodate substantial populations and infrastructures yet are frequently treated as peripheral to metropolitan innovation and policy.

The article explains why smaller cities have distinct resource profiles, governance capacities and relationships with surrounding territories. Their transitions cannot be inferred from large-city evidence because scale, institutional density, economic specialisation and regional dependency shape both constraints and opportunities.

The contribution establishes the rationale for the Lab’s later research on interconnected cities and metabolic geographies. It calls for comparative methods and policies that recognise smaller cities as active sites of transformation.