2.Appellant challenges dismissal of his writ petition in which he challenged revenue recovery proceedings referable to demand under the Kerala Building Tax Act, 1975, hereinafter referred to as the 'KBT Act', for short. As rightly noted by the learned single Judge, assessment proceedings was completed and demand made by the competent authority. The assessment was not challenged and that had become final. That being so, as held by this Court in Mother Superior, Congregation of Sisters of Charity v. Tahsildar, Mananthavady [1987 (1) KLT 841], a claim for exemption from payment of building tax on a ground referable to Section 3 of the KBT Act, cannot thereafter be raised. This position notwithstanding, looking into the materials, we see that the writ appellant/petitioner had actually conceded to the assessment