The Assessing Officer has to assess or reassess the income (“such income”) which escaped assessment and which was the basis of the formation of belief and if he does so, he can also assess or reassess any other income which has escaped assessment and which comes to his notice during the course of the proceedings. However, if after issuing a notice under section 148, he accepts the contention of the assessee and holds that the income which he has initially formed a reason to believe had escaped assessment, has, as a matter of fact not escaped assessment, it is not open to him independently to assess some other income. If he intends to do so, a fresh notice under section 148 would be necessary, the legality of which would be tested in the event of a challenge by the assessee. An Explanation to a statutory provision is intended to explain its contents and cannot be construed to override it or render the substance and core nugatory. Dismissing the appeal of the Revenue the Court held that  the basis of issuing notice under section 148 was on a wrong assumption of fact that the assessee had invested money with specified persons. The solitary reason recorded by the Assessing Officer for reopening of the assessment was deleted by the Commissioner (Appeals) and in such circumstances, the assessment under the other heads done by the Assessing Officer which were not shown as reasons for reopening was illegal. (AY. 2009-10)