The person concerned may furnish together with the application such document(s) or evidence(s) to establish that the amount of tax and interest, if any, paid on such tax or any other amount paid in relation to which such refund is claimed was not passed on by him to any other person – section 38(3)(b).
Further, to provide relief to taxpayers the above sub-section also provides that where the refund amount, as claimed, is less than Rs 5 lakh a self-declaration will only be required