Section 90(1)(i) in The Patents (Amendment) Act, 2002
(i)that the royalty and other remuneration, if any, reserved to the patentee or other person beneficially entitled to the patent, is reasonable, having regard to the nature of the invention, the expenditure incurred by the patentee in making the inventi n or in developing it and obtaining a patent and keeping it in force and other relevant factors;