Judgment :- J.B. Koshy, J. Petitioner constructed a building and construction was completed in 1995. As per the Building Tax Act the building is a taxable event on the completion of the construction. Therefore, petitioner filed return and building was assessed by Ext P1. Petitioner had paid the amount in instalments. Thereafter, Ext P3 notice was issued followed by Ext P4 order rectifying the assessment under S.15(3) of the Act on the ground that on the date of assessment rate of tax was changed. Normally, assessment should be based on the rate as fixed on the taxable event Here the taxable event is on the date of completion of the building and assessment was made correctly. 2. The Revenue relied on S.5(2) of the Act. But S.5(2) is applicable only for the buildings constructed before the appointed day when method of appointment was changed. The assessments were pending for whatever reason including filing of appeal Here, admittedly, the building was constructed after the appointed day and therefore, S.5(2) has no application at all and assessment can be made on the basis of taxable event. In this connection, I refer to the judgment of this court in O.P. No. 1631 of 1999. Apart from the above, the power of rectification is not a power of appeal. It is only correction of an error apparent on the face of record. In W.A. No. 1613 of 1988 it was held by a Division Bench of this Court that rate of tax is not a matter where power of rectification can be made by the authority. On that ground also the rectification order will not stand. The Original Petition is allowed and Exts. P3 and P4 are set aside.