A clean-fuel marine emissions regime covering the whole Pearl River Delta area has long been the goal of environmental officials. The recent switch by ocean-going vessels to low-sulphur marine diesel fuel when berthing in Hong Kong has brought it closer. Emissions of sulphur and respirable suspended particles of 10 microns or less were expected to fall by 12 and 6 per cent respectively as a result. Now a much bigger clean-air landmark is in sight, with the mainland’s ministry of transport having declared the entire delta a future emissions control area. Norwegian-made electric ferries ‘could reduce pollution in Hong Kong’s Victoria Harbour’ From January 2019, all vessels will have to switch to low-sulphur fuel while in Chinese waters. Hong Kong and Macau are not included in the PRD emissions control area, but a spokesman for the Environmental Protection Department says the city will adopt it, so that the requirement for low-sulphur fuel is no longer confined to berthing only. Hong Kong has made progress in reducing total air pollution from all causes, but marine and roadside fine-particle pollution remain potent contributors. Since the switch to cleaner fuel for berthing, the department says data shows sulphur concentrations in Kwai Chung, Tsuen Wan and Sham Shui Po are up to 50 per cent lower. Hong Kong air pollution still far exceeds WHO levels and worsening, concern group finds Evidence linking air pollution with cardiopulmonary disease and lung cancer is well documented. But a joint study by researchers from the universities of Hong Kong and Birmingham of more than 66,000 Hong Kong people aged 65 or older between 1998 and 2011 found that fine-particle pollution, caused mostly by road and maritime traffic, is putting elderly people at risk of dying from other kinds of cancer, for example of digestive organs and breast. There is a need to test the findings in other urban populations. That said, public health experts point out that air pollution is just one risk factor for cancer, with others such as diet and exercise more significant. The benefits of reducing marine pollution should prompt the government to redouble its efforts to upgrade local truck and bus fleets to combat roadside air pollution.