I was chatting with my neighbourhood kiranwala. After telling me how tough it was to manage his 'rolling' cash, he told me this story.
One of the people he deals with, a wholesaler in the Govandi area, one of the poorest sections of Bombay, saw that many of the disadvantaged who live there — particularly those without bank accounts and proper ID — were literally doing without food because the kind of grocery shops and hole-in-the-wall eating houses they would buy from wouldn't take their under-the-mattress money. So this guy mobilised his network of partners and supplier and arranged to get whatever sub-500 notes he could. He then exchanged these with the people of the area, taking a 10% margin on average.
He disbursed Rs 25 lakh in a day and made a tidy 2.5 lakh profit.