1. The validity of the Kerala Tax on Employment Act, 1976 (Act 14 of 1976) has been challenged in these writ petitions. The grounds of challenge raised in the various writ petitions may usefully be preceded by a brief survey of the provisions of the Act.

2.S.4 is the charging section. Clause (1) thereof, which is the main. provision, reads:

"4. Charge of tax (1) Subject to the other provisions contained in this Act, there shall be charged on every person who exercises a profession, art or calling or transacts business or holds any appointment, public or private, within the State, a half-yearly tax (hereinafter referred to as tax on employment) at the rate specified in the Schedule.

Explanation: A person shall be deemed to have exercised a profession, art or calling or held an appointment within the State, if that person has an office or place of employment within the State."

S. 5 provides for deduction of the tax on employment by the employer from the salary or wage payable to a person. S.4 provides for every employer liable to pay tax under S.5 obtaining a certificate of registration from the assessing authority. We skip over the provisions which provide for submission of