In the urban environment, residents’ health is damaged seriously due to fossil-fuel combustion, among the pollutants most are created from transport vehicles. Fuel cell buses fuelled by hydrogen appear to be a promise solution to environment, energy and public health problems that we face today. Studies worldwide point towards the technical feasibility of hydrogen as an energy carrier in the transport and stationary sectors, but several non-technical barriers need to be overcome or removed before hydrogen can be deployed in energy systems. This paper expounds a previous country-specific analysis by contrasting the challenges arising at EU level and those faced by transition economies, using China and Brazil as case-studies to identify the key barriers and potential impact on hydrogen fuel cell buses applications. The evaluation criteria used are described. Lessons on the critical conditions for a successful introduction of fuel cell buses and hydrogen into society and the establishment of a hydrogen infrastructure arise from the above analyses.