China is at the forefront of implementing pronounced decarbonisation practices to cut transportation emissions to fulfil its nationally determined contribution. The transport sector, the second largest emitting sector, accounts for 18.7% of the total greenhouse gas emissions in Hong Kong. Without ambitious decarbonisation efforts, transportation emissions and threat of climate change will not reduce significantly. Transportation system in Hong Kong differs from China in many facets, such as infrastructure, pollution standard, motor vehicle type and regulation. To reduce transportation emissions in the GBA over time, the region must emulate effective coordination and integration of transport policies for transformative changes.