U.L. Bhat, C.J.--1. First petitioner, a private limited Company, having a solvent extraction plant and consuming electricity for the plant for which electricity duty is payable under the M.P. Electricity Duty Act 1949 (for short the Act), has filed this writ petition challenging the vires of the note to the definition of 'factory' in item 2 (c) of the Table providing for rates of duty under the Act as introduced by M.P. Amendment Act 46 of 1984 and seeking direction for refund of higher duty recovered illegally from the petitioners. Return has been filed on behalf of the respondents.

2. Section 3 of the Act requires payment every month to the State Government duty calculated at the rates specified in the Table appended to the provision on the unit" of electrical energy supplied to consumers. Different rates have been prescribed for electrical energy sold or supplied for consumption in different kinds of purposes or premises. Consumption for business, trade or commerce purposes or for purposes of professional permits other than for flour mills, in premises of the factory, for purposes of illumintion for consumption in township or colony attached to the factory etc. are the different classifications. Even originally concessional rate of duty was applicable for supply or consumption in premises of factories depending on the strength of the connected load. The Act was amended by Act Nos. 21/75, 21/78, 46/84, 15/85.

3. As the Act originally stood, Explanation-C to section 3 of the Act defines 'factory' thus:

''Factory' means a factory registered under the Factories Act 1948 (No. 63 of 1948)." M.P. Factories Rules 1962 have been framed under the Factories Act 1948.

Rule 4 requires that no manufacturing process shall be carried on in any factory unless such factory is or is deemed to be duly licensed in accordance with the Rules. Rule 6 requires that not less than 15 days before the occupier begins to use any premises as a factory he shall make to the Chief Inspector an' application for registration and grant of licence along with notice of occupation in Form No. 4, in duplicate alongwith the treasury challan as a proof of payment of amount of fee specified in the Schedule. Rule 7 deals with the renewal of licence, Rule 9 deals with the amendment of licence and Rule 10 deals with transfer of licence. Rule 8 states that upon submission of an application under Rule 6, 7, 9 or 10 the premises in respect of which such application is made shall be deemed to be duly licensed, until the Chief Inspector has passed an order either granting or refusing to grant or renewal or amendment or transfer of the licence. The combined operation of the definition of 'factory' with rule 8 of the Rules was that concessional rate of duty for consumption in a factory was applicable on the date of application for registration of licence whatever be the ultimate fate of the application and whatever be the actual date of issue of licence. This was held so in M.P. No. 308 of 1980. It appears, meanwhile, the Central Government withdrew the electricity duty causing loss of revenue to the State exchequer.

4. In the above circumstances, the M.P. Electricity Duty (Amendment and Validation) Act 1984 was enacted. The statement of objects and reasons states thus:

"(1) The Central Government has withdrawn the excise duty on electricity with effect from 1.10.1984. This has resulted in loss of revenue to the State exchequer. To recoup partially this loss certain amendments in Madhya Pradesh Electricity Duty Act, 1949 had become necessary.

(2) The Madhya Pradesh Electricity Duty Act 1949 is silent as to when the registration of the factories under the Factories Act, 1948 shall be effective for the purposes of this said Act. The High Court of Madhya Pradesh in Misc. Petition (No. 308 of 1980) Municipal Corporation Jabalpur Versus Madhya Pradesh Electricity Board and State Government has held that the registration of factories as aforesaid with retrospective effect is