The numbers that you describe as English (1,2,3, ...) are not actually so. They are in fact originally from Arabic, but proved so useful that they have been adopted and used not only by Western languages, but also many Eastern languages, even those where there are longer-established alternatives (e.g. Japanese).

From your post Hindi would seem to be an exception to this. Dates will still need to be held in "standard international format" in the database, i.e. "yyyy-mm-dd", but you may be able to convert what visitors to your site see by changing the date functions in your hindi.php language file.

These are the functions that convert those internal dates into say mm/dd/yyyy for Americans and dd/mm/yyyy for most other people and can hopefully be adapted to convert them into hindi format too.