Exemption under section 10 limited where operative registration under the section eleven framework mandates exclusive regime selection. A trust or institution registered under section 12AA or 12AB and in force for a previous year cannot claim exemptions under section 10 except for agricultural income and specified clauses such as 10(23C), 10(23EA)/10(23EC)/10(23ED), 10(46) and 10(46A). Registration under section 11 becomes inoperative when approval or notification under those specified section 10 clauses takes effect. Such a trust may apply to make registration under section 12AA/12AB operative, but doing so terminates any prior approval or notification under the listed section 10 clauses, requiring an exclusive choice of regime.