Guangdong's Environmental Protection Bureau has fleshed out its ambitious plan to clean up the province's waterways. Officials say they will invest 44.6 billion yuan between now and 2010. It is a significant sum of money that will boost environmental spending to three per cent of the province's gross domestic product. Hong Kong stands to be one of the biggest beneficiaries of the scheme. The SAR is positioned at the receiving end of some of the most polluted waterways on the mainland and sources much of its drinking water from the East River, whose pure headwaters in Heyuan are much sullied after running the gamut of industrialised Huizhou, Dongguan and Shenzhen. The Pearl River, meanwhile, is hardly deserving of its name, as it is routinely ranked in mainland environmental surveys as part of one of the dirtiest major river systems in China. Under the cleanup scheme, upstream polluters have pledged to mend their ways. Guangzhou alone will invest 4.7 billion yuan by the end of next year on new sewage treatment facilities and the dredging of polluted river beds. It, and other cities, aim to raise the proportion of sewage they treat from less than a quarter at present to 70 per cent by 2010. Province-wide, Guangdong wants treatment levels to rise to 90 per cent of all industrial waste water and 60 per cent of all sewage. Moreover, Guangdong appears prepared to take the politically difficult step of forcing residential and industrial users - the latter including thousands of Hong Kong-invested factories - to bear much of the cleanup's cost through stiffer fees and charges. It is ultimately in their own self-interest, as at least one Hong Kong textile manufacturer discovered when it found it had to clean the water it sources from a local river before using it in dying operations. High-altitude photographs taken of the Pearl River Delta region reveal it to be a potentially beautiful landscape, laced by countless waterways. Up close, of course, the reality is rather different. But Hong Kong should be asking itself how it can support this long overdue effort, which promises to transform one of the world's most remarkable regions.