Exemption for power project inputs requires certification, security where provisional, restricted use pledge, and duty on misuse. Substitution of Conditions 26 and 28 requires certification of Ultra Mega and Mega Power Project status by a senior Ministry of Power officer; provisional certificates trigger a Fixed Deposit Receipt security in the name of the President of India for thirty-six months equal to the duty otherwise payable, subject to appropriation if final status is not obtained; Chief Engineer certification of goods' necessity is required with specification of quantity and description; and the project CEO must undertake that goods will be used only in the project and agree to pay duty if that undertaking is breached.