Tax exemption fund approval requires a trust deed, employee subscriptions, prescribed application procedure, and written approval conditions. A fund seeking approval for exemption under section 10(23AAA) must be constituted under a trust and evidenced by a trust deed. Employee contributions must be made by way of periodical subscription, and the application for approval must be filed in Form No. 9 before the Commissioner having jurisdiction where the accounts are kept, with the prescribed documents. Approval is granted in writing for specified assessment years, not exceeding three assessment years at a time; rejection requires recorded reasons and an opportunity of being heard.