There are 60 million millionaires in India, one for every person who lives in the UK. Yet the UN estimates that 638 million people still defecate outside. School drop out rates among women are higher in part because of the lack of adequate toilets - it is not the done thing for ladies to relieve themselves in public. Malise Ruthven argues that violence and revolution could follow if the problem is not addressed. Click here to read an extract of his fascinating article in The New York Review of Books.