If you don't know, you are new here and need to lurk moar.
I read that these were circulated to replace the old bills and break people who had stockpiled them. Something similar has been done in India, with the excuse of getting rid of black market money, the two largest bills that compromised 86% of circulating money were pulled, people were given a month to replace them, it totally screwed the population. Even more fukkery was done. When I do a straight-up Google search, I get nothing but absolute garbage. Google search Zero Hedge only has some of it:
Google search: India replace large currency zerohedge.com
https://www.google.com/search?q=India+replace+large+currency+zerohedge.com