C.N. Ramachandran Nair, J.

Two transporting agencies and the Ernakulam Chamber of Commerce representing transporting agencies generally are the petitioners challenging the constitutional validity of S.45B of the Kerala General Sales Tax Act, hereinafter called the "Act". While sub-s.(1) of the impugned Section provides for levy of penalty at double the amount of sales tax for transport of goods in Kerala without the documents prescribed under S.29(2) of the Act, for repeated offence, sub-s.(2) in addition to penalty provides for detention of the vehicle involved for a period of thirty days. The impugned section introduced to the Act with effect from 1.4.2000 is extracted hereunder for easy reference:

45B. Penalty for transport of goods without records.

(1) If any officer empowered under sub-s.(1) of S.29A finds on inspection of any vehicle or vessel that any transport agency or contract carriage transport any goods without the documents required under sub-s.(2) of S.29, such officer may without prejudice to any action that may be taken under S.29A, impose by an order in writing on such transporting agency, or contract carriage, or the owner of the vehicle a penalty equal to