Tax withholding obligation requires grossing up when payer bears non-resident tax and payment to government. Where a payer undertakes to bear a non-resident's tax, the payer must compute the recipient's taxable income by grossing up the net payment and deduct tax on that grossed up amount at source each time a payment is made, and remit the deducted tax to the credit of the Central Government without withholding on the premise of later payment on assessment.