Transformative leapfrogging in urban infrastructure – Learning from a de facto experiment with water reuse solutions in Bengaluru

Middle-income cities (MICs) are characterized by rapid urbanisation, expanding innovation capacities, and relatively weak path dependencies in their urban infrastructure systems. This could create unique opportunities for transformative leapfrogging – bypassing conventional infrastructure solutions in favour of novel, more sustainable approaches. Yet, most MICs tend to replicate global gold standards rather than embark on complex innovation trajectories. We argue that conventional urban planning and transitions concepts are ill-suited to address how to foster transformative leapfrogging in MICs and develop a novel analytical framework that combines socio-technical transitions theory with insights from innovation systems research. The framework highlights the creative problem-solving capacity of actors in dynamic MICs and specifies under what conditions experimentation with second-best solutions may lead to new transformative infrastructure templates. We apply the framework to a case study of how decentralized wastewater treatment and reuse systems have gained significance in Bengaluru (India). Drawing on 54 interviews, 23 site visits and 6 workshops, we show how regime-defying policies were introduced in response to development pressures and outline the factors triggering a de facto experimental space, in which actors could experiment with new solutions at scale. We then show that systemic barriers still hamper their maturing. We sketch an alternative approach to transformative leapfrogging in MICs that represents a shift from conventional planning logics and niche-focused transition models towards actively leveraging the ingenuity and problem-solving capacity generated within rapidly evolving urban contexts.