Tax exemption recognition under section 10(23C)(iv) subject to income application, permitted investments, incidental business, filings, and dissolution transfers. Notification recognises Petrotech under clause (23C)(iv) of section 10 for specified assessment years on conditions requiring exclusive application of income to its objects, investment of funds only in permissible modes (with an exception for certain voluntary contributions retained as movable assets), exclusion of business income unless incidental and separately accounted, regular filing of income-tax returns, and transfer of surplus and assets to a similarly purposed charitable organisation on dissolution.