Notice on erection of building etc.

When any new building is erected, or any existing building is reconstructed or altered or improved, or when any building which has been vacant is re-occupied, the person primarily liable to pay tax under this Act shall give notice thereof in writing to the Executive Officer within fifteen days from the date of its completion or occupation, whichever first occurs or as the case may be, from the date of its alteration, improvement or re-occupation and the tax shall be assessable on the building from the said date.