S. 148A: Reassessment-Conducting inquiry, providing opportunity before issue of notice-Territorial Jurisdiction-Notice issued by Assessing Officer outside territorial jurisdiction of High Court-Notice served on petitioner who is assessee within territorial jurisdiction of High Court-Petitioner required to defend notice issued on it at Mumbai-Part of cause of action arising within territorial jurisdiction of High Court maintainable-Notice-Amalgamation of companies-Notice issued to non-existent amalgamating company Intimation of amalgamation given to Department-Reassessment proceedings cannot be initiated against non-existent entity-Notices and order invalid and non est.[S. 147, 148, 148A(b),148A(d), Art. 226]