S. 153A: Assessment-Search-No incriminating material found during search of assessee-Material seized from third party cannot form basis of assessment under section 153A-Assessment invalid-Return filed in response to notice-Revised computation during assessment-Addition based on difference from original return-Not justified-Undisclosed income-Sale of plots-Transactions duly recorded in books-No evidence of suppression-Addition deleted-Unexplained expenditure-Development expenses-Assessee only landowner-Expenditure incurred by associates-Addition deleted-Cash credits-Sale proceeds of plots deposited in bank-Source explained-Enhancement of profit by Commissioner (Appeals) deleted-Inter-bank transfer-Amount taxed twice as unexplained credit-Addition deleted-Cash credits-Documentary evidence explaining source-Addition restricted to profit element upheld. [S. 68, 69, 69C, 132, 139 153C]