Here's how RBI executed decision to demonetise high-value currency notes

Over 99% of banned notes came back into the RBI's currency chest

According to the RBI, the work between November 8, 2016 (the date on which the currency ban was announced), and December 31, 2016, and even beyond, was efficiently carried out. 

With tight deadlines, the RBI says it worked under enormous pressure to take back the banned notes after screening them and then quickly re-filled the system with new notes to ensure minimum hardship to people.

RBI frequently issued guidances about the procedure for returning the banned notes (over 50 times in a span of 50-odd days). One of the guidances issued by the RBI made it mandatory for a person to get