Section 40(a)(i) of the Income-tax Act, 1961, deals with the disallowance of certain expenses in computing the income chargeable under the head 'Profits and gains of business or profession'. Specifically, it targets payments made outside India or to a non-resident, which are subject to tax deduction at source (TDS) under Chapter XVII-B. If the tax is not deducted or, after deduction, not paid within the prescribed time, the corresponding expenditure is disallowed as a deduction. This provision ensures compliance with TDS obligations and prevents revenue leakage. The burden of proof lies on the taxpayer to demonstrate compliance with TDS provisions. Practically, this section is significant as it affects the cash flow and tax liability of businesses engaged in international transactions.