Withholding tax limits on cross-border dividends, interest and royalties permit treaty-based reduced source taxation with prescribed certification procedures. The Supplementary Protocol limits source-country taxation on dividends, interest, and royalties and fees for technical services when the beneficial owner is a resident of the other Contracting State and the income is not effectively connected to a permanent establishment or fixed base. Treaty relief from Belgian tax requires Forms 276 Div.-Aut. or 276 Int.-Aut. certified by the Indian Assessing Officer and timely submission for reduced withholding or refund; relief from Indian tax requires a Belgian certificate of residence (Form 276, Conv) to enable deduction at the treaty rate or a refund claim if excess tax was withheld.