Petitioner is challenging Exts.P6 & P8 assessment and demand of building tax along with interest. This is the second writ petition filed by the petitioner in the same matter. In the first round this Court directed 2nd respondent to consider petitioner’s claim for exemption of factory building. However, building was let out for commercial purposes and therefore, exemption is rightly declined. What remains is petitioner challenging against interest. Third respondent has wrongly relied on Section 3B of the Act, which is not applicable in this case. However, interest is payable for belated payment of tax @ applicable under Section 19(1) of the Kerala Building Tax Act. Moreover, interest will be payable for the complete period of default after first assessment and not from date of completion of construction as held by 2nd respondent in his order. This writ petition is accordingly allowed in part directing 2nd respondent to re-compute interest on the building tax @ prescribed under Section 19(1) of the Act from the date of default after service of first notice of demand along with assessment order and recover