Worldwide, one billion people live in slums. By 2050, it might be two billion. India has the world’s second largest slum population, after China. In 2009, the government launched a plan for a ‘slum free India in five years’: since then, slum growth has continued unabated. Mumbai has more than nine million slum inhabitants, up from six million ten years ago. In the face of such statistics it is easy to be pessimistic. Yet most slums are hives of economic and political activity. Shack/Slum Dwellers International and its president, Jockin Arputham, have been nominated by the Swedish housing minister for this year’s Nobel Peace Prize.