Just look at how it has been solved in Scandinavia, Estonia etc. I don't know enough about Indian Aadhar (?), but I assume that works as well. And start keeping

Just look at how it has been solved in Scandinavia, Estonia etc. I don't know enough about Indian Aadhar (?), but I assume that works as well. And start keeping a decent registry of people instead of relying on a once a decade census.