Reciprocal tax exemption for airlines ensures mutual income tax exemption on international air transport, with refunds if tax was collected. Reciprocal exemption from income tax for Indian and Iranian airline companies is established by exchanged notes dated 1973 and is to be applied domestically; the exemption covers income from transportation of passengers and goods in international traffic, operates from the commencement of each party's airline operations in the other State, and requires refund of any tax already recovered by either Government in respect of such income.