Victoria Harbour could be polluted with raw sewage if WTO, protesters attack treatment facilities in Wan Chai near the venue of the World Trade Organisation ministerial conference, the director of drainage services said yesterday. But Wong Chee-keung quickly sought to dampen fears, saying 'the flushing capability of Victoria Harbour is very strong'. The department said one of its scenarios was attacks on two sewage treatment stations next to Wan Chai Sports Ground and the Society for the Prevention of Cruelty to Animals, both near the Convention and Exhibition Centre. Police will guard both facilities. Manhole covers in the area have also been sealed to prevent concrete being poured into pipes.