Black markets for things exist,' he said slowly, as if confiding a personal secret rather than a commercial fact, 'because the white markets are too strict. In this case, in the case of currencies, the government and the Reserve Bank of India control the white markets, and they're too strict. It's all about greed, and control. These are the two elements that make for commercial crime. Any one of them, on its own, is not enough. Greed without control, or control without greed won't give you a black market. Men can be greedy for the profit made from, let's say, pastries, but if there isn't strict control on the baking of pastries, there won't be a black market for apple strudel. And the government has very strict controls on the disposal of sewage, but without greed for profit from sewage, there won't be a black market for shit. When greed meets control, you get a black market.