S. 143(3): Assessment-Amalgamation-Assessment orders passed in names of amalgamating entities-Amalgamation approved by court was informed to Department with date and other details-assessment orders issued in names of non-existent entities void ab initio-Jurisdictional issue-Additional ground was raised first time before High Court-Additional ground was admitted-Interim applications allowed-Appeals by Revenue and assessee’s writ petition rendered infructuous.[S. 143(3), 254(1), 260A]