Held that the  jurisdiction of the Assessing Officer is confined to assessing issues on which he has reason to believe that income has escaped assessment and it is only if during the course of assessing these incomes that he is made aware of any other income escaping assessment that he can assess the other such income also. The issue raised by the Principal Commissioner being not the subject matter of reassessment nor having come to the notice of the Assessing Officer during the reassessment proceedings, the Assessing Officer could not have considered this issue in the reassessment proceedings. Therefore the assessment order passed under section 147 of the Act could not be said to be erroneous on the ground of the Assessing Officer not having examined an issue which clearly was beyond his powers. The order passed under section 263 of the Act was accordingly not sustainable in law.(AY. 2012-13)