In the wake of this spring's battle with Sars, and in the face of evidence that environmental factors may have contributed to the seriousness of the outbreak in Hong Kong, the government set up Team Clean and appointed Chief Secretary Donald Tsang Yam-kuen to head it. The team's task: to improve public hygiene throughout the city, including the numerous government-run housing estates. A system of demerit points for public housing tenants was introduced as part of the team's package of measures. While most of that system has been enforced since the beginning of August, a two-month grace period was applied to one crucial part: demerit points for pet ownership were held back because of vocal opposition from tenants and animal rights groups. The grace period on the pet ownership rule is set to expire within weeks, so now is the time for the government to let the tenants and the public know about its plans for bringing these rules into effect. Public hygiene should remain the highest priority and there is no question that this means standing tough on certain rules even if they prove to be less than popular. However, in the case of the pet ban, there are complicating factors. The rules against pet ownership have long been written into tenancy agreements but have been widely ignored by both the Housing Authority and by tenants. The result: possibly tens of thousands of families living in public housing have one or more cats or dogs. Sudden enforcement of the rules could mean pets are tossed out on the streets, creating a public hygiene hazard of a kind the government may not have expected and for which the city may not be prepared. Animal welfare groups have called the plans cruel, while a number of pet- owners have also hit the streets to protest. There are a variety of compromises that could help ease those anxieties while furthering the cause of public hygiene and health. These include introducing a grandfather clause that allows existing pet owners to keep their pets, subject to requirements such as registration and adherence to cleanliness and nuisance rules. There could also be limits placed on the number of pets allowed. Any new rules will need to be realistic and enjoy broad support; otherwise, they could be as widely flouted as the old ones. It has been several months since Hong Kong's brush with Sars and it may be difficult now to remember the atmosphere in which Team Clean's recommendations were introduced. But the recent scares over the possible resurgence of the virus should remind us of the very real possibility that Sars will return or that an equally dangerous new disease may emerge. In this light, vigilance on the hygiene front is crucial and resolution of the public-housing pet-ban issue would be in everyone's interests.