Dismissing the appeal the Court held that   as found by the Tribunal the notice dated March 27, 2008 under section 148 for reopening the assessment under section 147 for the assessment year 2001-02 was not issued at the correct address of the assessee. Such notice, sent by speed post, but having not been returned unserved, would be of no avail since the address given in the notice was not the last known address of the assessee. No provision in the Act obliged the assessee to ensure that his changed address was entered in the permanent account number database failing which he was precluded from insisting on the notice under section 148 being issued to him at the known address and being served upon him. For the assessment year 2005-06 and the subsequent assessment years, the assessee had disclosed his new address. The Assessing Officer had sent letters and the intimation under section 143(1) dated January 25, 2008 for the assessment year 2006-07 at the new address of the assessee. Hence, though the Assessing Officer was aware of the change of address of the assessee, he had issued the notice under section 148 at the old address. No legal error was committed by the Tribunal in holding that there was no proper service of notice on the assessee under section 148. The requirement of both the issuance and the service of notice upon the assessee for the purposes of sections 147 and 148 of the Income-tax Act, 1961 are mandatory “jurisdictional requirements”. The mere fact that an assessee participated in the reassessment proceedings despite not having been issued or served with the notice under section 148 in accordance with law will not constitute a waiver of such jurisdictional requirement. CIT v. Chetan Gupta (2016) 382 ITR 613 (Delhi)(HC)  and R. K. Upadhyaya V. Shanabhai P. Patel (1987) 166 ITR 163 (SC) . (AY.2001-02)