No large data centre that worth the name didn't prepare for that. In case of massive power faiture, the entire chain from grocery stores up will be shut down to prevent transaction record loss

The main difficulty with india has to do with grass root tax evasion and bribery

In Bharat,

Low level bribery currency--paper money

Mid-level bribery currency--high denomination paper money(which modi wants to ban) and precious metal

Top level bribery medium--Swiss/caribbeans bank accounts through money laundry