Hong Kong has prohibited new registration of fossil-fueled private cars by 2035 or earlier. But there remains plenty of work to be done to enhance ambition and forge a more sustainable transport system. Photo by Phan Hoang Phe/Unsplash In densely urbanized Hong Kong, transport is the second largest source of greenhouse gas emissions, at 18%. Vehicle traffic is also a major source of toxic air pollutants like NOx, volatile organic compounds and carbon monoxide, accounting for 18%, 21% and 50% of total emissions in 2018, respectively, and a key contributor to public health risks. As a result, Hong Kong moved in March to prohibit new registration of fossil-fueled private cars by 2035 or earlier.