Introduction Economic globalisat ion has becom e 'a strong forc e' dri ving th e urban developm ent of Asian countries. T he formation of megac ities which have 10 million or more inh abitants, or a new class of urban agg lomera t ion of Extended M etrop olit an Regions (EM Rs), has inc reased in number and scale (McGee , 199 1, 1995; Douglass, 2000 ). It is estima ted th at th e urb an populat ion in East Asia wi ll increase by approxima tely 200 milli on peo ple over th e next twent y-five years , of which 40 % will occur in th e peri-urb an area (PUA).I Th e enviro nmenta l challenges of th ese megaciti es - high rat es of land an d energy consumption, severe pollution of air, water and soil, and decrease of qu alit y of life - have becom e of increasing concern (Marco t ullio, 2001 ; Yueng, 2001 ; Webster, 2002; Ng and Hi lls, 200 3).