For a great podcast leading up to this, you should listen to
http://www.npr.org/sections/money/2017/05/10/527803742/episo...
http://www.npr.org/sections/money/2017/05/12/528181998/episo...
http://www.npr.org/sections/money/2017/05/10/527803742/episo...
http://www.npr.org/sections/money/2017/05/12/528181998/episo...
Here is history of demonetisation in India from Wikipedia-
"The Indian government had demonetised bank notes on two prior occasions—once in 1946 and then in 1978—and in both cases, the goal was to combat tax evasion by "black money" held outside the formal economic system.[19] In 1946, the pre-independence government hoped demonetisation would penalise Indian businesses that were concealing the fortunes amassed supplying the Allies in World War II.[19] In 1978, the Janata Party coalition government demonetised banknotes of 1000, 5000 and 10,000 rupees, again in the hopes of curbing counterfeit money and black money.[20]
In 2012, the Central Board of Direct Taxes had recommended against demonetisation, saying in a report that "demonetisation may not be a solution for tackling black money or economy, which is largely held in the form of benami properties, bullion and jewellery."[21][22] According to data from income tax probes, black money holders kept only 6% or less of their wealth as cash, suggesting that targeting this cash would not be a successful strategy.[23]" https://en.wikipedia.org/wiki/2016_Indian_banknote_demonetis...