I was talking to a guy from India and he said that you can't use the exchange rate with the USD to get an accurate idea of who this policy is targeting. These rupee notes function like the $100 note does here and is similarly used by the rich to transfer wealth under the table to avoid taxation, which is apparently a national pastime that favors the haves far out of proportion to the have nots. Think suitcase full of stacked Benjamins, not mason jar in the cupboard with rumpled twenties and tens.
Apparently there are white and black pools of money and it's common for purchases of high value items, like BMWs and gold jewelry, to be made with both, with a portion of the purchase price reported on the official books as a white money transaction, while the remainder is paid in black money under the table.
This guy said that this is an attempt to reduce the epidemic of under the table transactions by rendering the necessary stack of money too high to fit under the table. He's also confident that the black money will find a work around, eventually.
I had a similar conversation. No shortage of people from India in my line of work.
Though the fellow I was chatting with was strongly in favor of this, as even small shop keepers commonly don't declare cash revenue.
I was polite about it, but India lacks competent government institutions (yes, USA has top shelf .gov agencies in contrast). There are protection rackets, and tip-offs from insiders.
Imagine if you owned a coffee shop, for $100/year an IRS insider will alert you if you are ever under investigation.
Beyond that, there's no inventory control, chain of custody for materials, etc.
In the USA, Bob is a cabinet maker and buys his wood from someplace. If Bob attempts to embezzle from his company, perhaps claiming his sales were way down, all while pocketing the revenue off the books, upon investigation auditors would surely ask where all the raw materials (lumber) went. If Bob falsified receipts, the lumber yard might be subpoenaed, etc.
Since most of the supply chain in a place like India is gray market at best, this sort of investigation is nearly impossible.