The Sars outbreak taught us the importance of keeping Hong Kong clean. It does not seem that long ago that Donald Tsang Yam-kuen, now chief executive but then chief secretary, led the Team Clean campaign to clean up the city in the wake of the killer virus. The outbreak prompted a new sense of urgency and responsibility, but the test was always going to be whether this could be sustained. This is why our report today on the shameful scene at one of our best-known beaches on Tuesday is worrying. Deep Water Bay, open all year and recommended by the Tourism Board to millions of visitors, was ankle-deep in plastic bags, drink cans and other debris. There was no escape in the water, which was fouled by slicks of floating junk. Mr Tsang's Team Clean cashed in on the post-Sars spirit to launch a broad attack on filth. It was not afraid to make tough decisions and adopt measures, such as fines for spitting, that were bound to attract strong opposition from certain sectors of the community. For a time it appeared that the campaign might be making progress towards the goal of making our city the cleanest in Asia. It seemed that fear of the deadly virus had helped awaken community awareness of cleanliness and hygiene. Sadly, the recent heavy rainfall has destroyed that illusion, flushing Hong Kong's dirty laundry - its rubbish - off the land and into and around its shorelines. As leading conservationist Markus Shaw of WWF Hong Kong says, Deep Water Bay, next to Ocean Park, is one of the first impressions that visitors to Hong Kong get. But it seems to have become the city's dustbin of last resort. Think-tank chief Christine Loh Kung-wai is right to call for a renewed community-wide effort to reduce the amount of rubbish washing up on beaches. 'It is a matter of community will ... When we had Sars, people wanted to clean up.' It is understandable that we have put the Sars experience behind us. But in a world living with the fear of a flu pandemic, drug-resistant bacteria and mosquito-borne diseases - to name a few health threats - it is regrettable that we seem to have forgotten hard lessons about the importance of civic cleanliness. A study on rat infestation by the Food and Environmental Hygiene Department released earlier this month was a reminder that we cannot relax our vigilance. In six months Queen's Road Central went from being apparently rat-free to one of the city's worst-affected areas, although the overall infestation rate had dropped. Team Clean stopped functioning early last year, although most of its initiatives continued. But it seems we were deprived too soon of its driving, co-ordinating force behind reforms, creating potential for the war on filth to become fragmented again. The scene at Deep Water Bay was a wake-up call to the government that the war is far from won.