Megacities have particular significance in this world-wide process of urbanisation, new scales have evolved ("mass matters"): In the year 2015, more than 600 million people will be living in about 60 megacities worldwide (i.e. metropolises with more than 5 million people). More than two-thirds of the megacities are located in deve- loping countries; their populations have increased greatly in the last three decades (UN 2002, Kraas 2003, Bronger 2004). In the next 20 years, not only the most inten- sive growth rate and megaurban development processes are predicted for East Asia, South Asia, and Africa but also the highest numbers of megacities will be located in parts of Asia (Fig. 1, Fig. 2).