Judgment :- C.K. Abdul Rehim, J. The Challenge is against Ext.P10 order of assessment issued under the provision of the Kerala Building Tax Act, 1975. The petitioner purchased the building in question during the year 1995. According to the petitioner, the construction of the building was completed in the year 1993. The authorities have assessed Building Tax through Ext.P2 order and the petitioner and remitted the amount so assessed, in four equal quarterly instalments, as evidenced from Exts.P4 to P7 receipts. Thereafter in January, 2004, the petitioner was served with Ext.P8 notice requesting him to be present in the office of the second respondent with relevant records for the purpose of assessment of building tax with respect to the very same building. According to the petitioner, when he appeared before the second respondent he was informed that, the proceeding is initiated only for correction of a mistake and there will not be any further action. But Ext.P10 assessment was made thereafter, imposing a total tax liability of Rs.73800/-. After giving credit to the amount of Rs.27,000/- already remitted, a balance amount of Rs.46,800 was demanded. The petitioner is challenging Ext.P10 order of assessment and the consequent demand. 2. Heard Sri. P.K. Sajeev, learned counsel for the petitioner and Sri.Mohammed Rafeeq, senior Government Pleader appearing for the respondents. In the statement filed by the second respondent it is submitted there occurred a clerical mistake in calculating the building tax in the earlier assessment, to the extent that the building in question was included in the category of “residential buildings” instead of the category of “other buildings.” The said mistake was noticed only at the time of the verification by the inspecting team of the Land Revenue Commissionerate. Further it is stated that, the total plinth area was found to be 566.025 square meters, during the subsequent inspection, which according to the second respondent, is due to additional construction made by the petitioner after the first assessment. Therefore, there is a short levy of building tax and hence Ext.P10 assessment is made, is the contention. The petitioner filed reply affidavit mainly disputing the aspect that there was additional construction made after the earlier order of assessment. 3. The sustainability of Ext.P10 assessment need be examined in two angles. Firstly, whether an order for a rectification of mistake and assessment for additional construction, can be made through a single composite proceedings. The petitioner filed reply affidavit mainly disputing the aspect that there was additional construction made after the earlier order of assessment. 3. The sustainability of Ext.P10 assessment need be examined in two angles. Firstly, whether an order for a rectification of mistake and assessment for additional construction, can be made through a single composite proceedings. On an evaluation of the scheme of the Act it is clear that a detailed procedure is contemplated for making assessment of building tax due on completion of a building. Section 7 to 9 of the Act deals with the procedure, starting from filling of return by the assessee upto issuance of order of assessment and demand notice. The same procedure need be followed in case of assessment of Building Tax with respect to a building to which major addition or alteration is effected, subject to the provisions contemplated in section 5(4), Wheareas section 15 of the Building Tax Act provides that if there is any mistake in the assessment, which is apparent on the face of the records, the same can be rectified within a period of three years. The proviso to section 15 mandates that such rectification could be made only after issuing notice to the assessee and after affording a reasonable opportunity of hearing to him. Therefore it is clear that the procedure contemplated under the scheme of the Act in both cases are distinct and separate. The rights and liabilities of the authorities and the assessee are also entirely different in both the cases. So a single order without differentiating the two liabilities issued without complying with all the required formalities, in violation of the specific procedure contemplated for both purpose is absolutely illegal and unsustainable. 4. Secondly, Ext.P10 need be tested on the basis as to whether it had fulfilled the required procedural formalities, before its finalization. Ext.P8 notice does not reveal that the proposed action is for rectification of any mistake, nor it disclosed the ground for such rectification proposed. If any additional construction is made to a building with respect to which assessment has already been completed, a fresh assessment has to be made in view of the provisions contained in section 5 of the Act, following the procedure prescribed in section 5(4). For making such an assessment the procedure contemplated under sections 7 to 9 of the Act, need be resorted to. For making such an assessment the procedure contemplated under sections 7 to 9 of the Act, need be resorted to. Ext.P10 order cannot be sustained since it has not complied neither with the mandates of section 15, nor with the procedures prescribed in section 7 to 9. 5. Under the above circumstances Ext.P.10 is quashed. Needless to observe that this will not preclude the second respondent from proceeding against the petitioner for rectification of mistake in Ext.P2 order, if permitted under law, and also from making fresh assessment in accordance with law on the basis of the additional construction, if any made.