The Indian govt. could try a US govt. like gold seizure program, which if memory serves me correct, US govt. did at some point in early 1900s - it was illegal to own more than a certain maximum quantity of gold in any format ( except for the limited edition golden eagles US mint used to release back in the day) and that amount was just a few grams. Forced US citizens to hand over literally tonnes and tonnes of gold to the US govt.
But ofcourse, this wont ever happen in our lifetime, because the day the govt announced this plan, the PM- whomever is the PM- will get lynched Mussolini style and hung from india-gate, at least for the duration of our lifetimes.