Section 5(2)(ii) in The Kerala Buildings (Lease and Rent control) Act, 1965
(ii)any non-residential building, excepting a building to which fittings have been affixed or in which machinery have been installed and such fittings or machinery have been excluded from valuation the purpose of fixing the property tax or house tax by a local authority, the fair rent fixed may in proper cases be lower than but shall in no case exceed by more than fifteen per cent, the monthly rent on the basis of which the property tax or house tax for the building prevailing two years immediately before the date of the application was fixed, or if the building was not assessed to property tax or house tax before the said period of two years, the monthly rent on the basis of which the property tax or house tax prevailing immediately before the date of the application was fixed.