Mumbai has some of the most expensive real estate in the world, but in contrast to major cities, this is a metropolis where a slum and a posh neighbourhood can share a fence. Walk out onto the balcony of a top floor penthouse in upmarket Pali Hill, where Bollywood stars rub shoulders with businessmen, and the view below could be that of shanties — thousands of roughly built shacks with corrugated tin roofs, and the smoke from camp fires cooking the day’s food.