How do I clear my Apple Account balance to zero?

Here's a couple of ways you can make your account zero (0 rupees):

(1) You can purchase an item that costs more than your balance and use a payment method for the rest.

or

(2) Apple support's article: (Re: change your country or region)

Check your Apple Account balance - Apple Support

says:

" If your balance is less than the cost of a single item, contact Apple Support."