The Star Ferry is a Hong Kong icon, as much a part of our history as a tourist attraction. As such, it should be striving to reduce the amount of air pollution created by its ferries. The same goes for other vessels plying their trade in our waters. The unsightly black smoke that pours from their funnels is a poor advertisement for our environmental awareness and the government's commitment to clearing skies of smog and protecting health. Authorities have to regulate the sector and help firms use cleaner fuels and technology. There is no more polluting fuel than the bunker oil burned by large vessels, which is many times more harmful to health than the emissions from even the dirtiest diesel used by buses and trucks. The public policy think tank Civic Exchange estimates that 3.8 million people are at risk of being exposed to excessive levels of emissions of sulphur dioxide, nitrogen dioxide and other pollutants from shipping and the port at Kwai Chung. Despite this, though, ocean-going shipping remains the only transport sector still unregulated by the government. There is no good reason why ferry and shipping companies should not use cleaner fuel. The irony is that many want to, but need the authorities to help with regulations, supplies of cleaner fuels and infrastructure. The objective has to be to ensure that all vessels in our waters at least use ultra-low sulphur diesel. It has a sulphur content of no more than 0.005 per cent, considerably less than the 0.5 per cent that ferries and small craft are required to use. Bunker fuel can have as much as 4.5 per cent. Voluntary schemes are under way and trials have been held. Under the industry-led, unsubsidised, Fair Winds Charter, a number of shipping and cruise lines have agreed to use fuel with a sulphur content of 0.5 per cent or less while at berth in Hong Kong until the end of next year. After a trial use of ultra-low sulphur diesel in its vessels proved unsatisfactory due to engine incompatibility, the Star Ferry Company is engaged in work with the University of Hong Kong to improve scrubber technology. However, as worthwhile as such measures are, without government regulations and assistance, there can be no guarantee of their permanent adoption. Costs are an obvious concern. Ultra-low sulphur diesel or fuel cleaning technologies are more expensive and the charges are likely to be passed on to consumers of goods carried by ships and ferry passengers. That is especially troublesome for ferry operators, who have low profit margins. But authorities cannot sit on their hands and expect every company to volunteer. Incentives and help with infrastructure will be necessary. Ultimately, though, regulating for clean emissions is essential for Hong Kong's well-being and image.