S. 148 : Reassessment-Notice-Service of notice-Mandatory-Assessing Officer though aware of new address of assessee issuing notice at old address-No statutory obligation on assessee to update address in Permanent Account Number database-Participation in reassessment proceedings without service of notice does not validate notice and proceedings-Order of Tribunal quashing the assessment is affirmed. [S. 143(1), 147, 149(1)(b), 260A, 282(1), 292BB, Civil Procedure Code, 1908, Order V, rule 12]