Hong Kong has the expertise and financial clout to tackle its pollution challenges. Victoria Harbour is proof of what can be done when there is also will. A quarter of a century ago, its waters were hazardous to health; now, in some places, it is safe to swim. Those achievements should not be allowed to falter through unnecessarily delaying schemes or baulking at reasonable costs. Environment officials believe that water quality has improved so much that there is no need for now to go ahead with an upgrade of the centralised waste treatment system. It would have added biological methods to the present chemical-based ones, keeping in line with international standards. But authorities contend that such a scheme is not at this stage critical and the focus should instead switch to preventing illegal water discharge and stopping sewage from old buildings from going into the harbour. Whether biological management is required will instead be reviewed. University researchers found last year that bacteria measurements at all 10 harbour locations tested in a study were far too poor to allow swimming. While water quality has improved at the eastern end to permit a cross-harbour competition, the original route until it was abandoned in 1979, from Central to East Tsim Sha Tsui, had levels 92 times beyond what the Environmental Protection Department considers suitable. The upgrade of the Stonecutters Island treatment works so that nutrients behind high readings could be removed from effluent was recommended by an international panel 12 years ago. Implementation would cost at least HK$30 billion. Unlike air pollution, it is difficult to determine from a distance just how poor the water in the harbour is. Cloudiness, a bad smell and floating litter are noticeable only from close up. But that is no reason to treat the two differently; every effort has to be taken to make both as clean as possible. The health of our environment is intrinsically linked to our own well-being. New ways of dealing with environmental problems are constantly being found through improved technology. This was one reason given for the water treatment review. Cooperation with Guangdong authorities to clean up the Pearl River also means less pollution is flowing into Hong Kong waters. Great strides have been made, but the harbour will not again teem with fish, nor will we be able to properly enjoy its waters, without determined and sustained effort.