Shenzhen ditched diesel buses and went electric in 2017 - a world first - with its taxi fleet not far behind. Other Chinese cities have followed suit with many aiming to switch before 2025. Electrification is one of the most important strategies to reach net-zero carbon emissions by 2050, according to International Energy Agency (IEA), with bus decarbonisation representing five per cent of cumulative emissions reductions in transport. A World Bank case study on SZBG, the city's largest public transport operator, found emissions from an e-bus in its service time were 52 per cent that of a diesel bus.