Export duty exemption for iron ore limits customs duty to a specified ad valorem rate on exports. The notification exempts iron ore of all sorts under heading No. 11 of the Second Schedule to the Customs Tariff Act, 1975, when exported from India from so much of the duty of customs leviable thereon as is in excess of the amount calculated at the rate of 5% ad valorem, thereby limiting duty liability on iron ore exports to that ad valorem rate.