Cities are packed with people . Eduardo Paes : More than half the world 's people now live in cities . Paes : Cities must be environmentally friendly , must provide solutions to waste , pollution . Rio is ' ` ` bus rapid transit '' as an alternative to building costly subway lines , he says . He says cities must be integrated socially , must take advantage of technology .
Eduardo Paes : More than half the world 's people now live in cities . Paes : Cities must be environmentally friendly , must provide solutions to waste , pollution . Rio is ' ` ` bus rapid transit '' as an alternative to building costly subway lines , he says . He says cities must be integrated socially , must take advantage of technology .