Hrishikesh Roy, J.

1. The levy of electricity duty under the Assam Electricity Duty Act, 1964 (hereinafter referred to as the "Duty Act") is challenged by the petitioner companies, who generate electricity during power failure, to continue the operation of their cellular phone service. As the taxable event under Section 3(1)(c) of the Duty Act, is on generation of electricity, the petitioners question the legislative competence of the State, to levy tax on power produced by them for captive consumption, by referring to the relevant entries in the lists of the Seventh Schedule to the Constitution of India. The burden of electricity duty on cellular phone service provider is contended to be discriminatory since, unlike the power companies, who are subject to such electricity duty, the cellular companies/or those providing infrastructure support to them, do not supply electricity on commercial basis, to others. Since uninterrupted cellular service is essential for their business module, the operators are compelled to arrange back up generation of electricity on account of failure of the State's power company to provide uninterrupted power supply, notwithstanding the