The Indian government banned the use of its two highest demonination notes (the 500 and 1,000 rupee notes) today to discourage the black market operators. I'm thinking there are a lot of Indians who are buying gold/silver/any other currency right now.
put everything from the last 5-6 years together and it's clear that governments are on the road to block ppl from using cash. Not so against black market, but rather against money that sits around beyond their monitoring / control / power.