Visit any burgeoning city in thedevelopingworld from Shanghai to Mexico City and the same reality emerges: as cities get larger, they spread out, as people begin to aspire, as best they can, for the quality of life that most North Americans and Europeans already take for granted.
More than 70 percent of city dwellers in thedevelopingworld (that's around 900 million people) live in slum-like conditions, according to theWorld Health Organization (WHO).