Dismissing the appeal of the Revenue the Court held that the determination of tariff between the assessee and the State Electricity Board could not be said to be an exercise between a buyer and a seller in a competitive environment or in the ordinary course of trade and business, i. e., in the open market. Such a price could not be said to be the price determined in the normal course of trade and competition. The market value of the power supplied by the assessee to its industrial units should be computed by considering the rate at which the State Electricity Board supplied power to consumers in the open market and not that at which it was sold to a supplier, i. e., sold by the assessee to the State Electricity Board, as this was not the rate at which an industrial consumer could have purchased power in the open market. The rate at which power was supplied to a supplier could not be the market rate of electricity purchased by a consumer in the open market. On the contrary, the rate at which the State Electricity Board supplied power to the industrial consumers had to be taken as the market value for computing deduction under section 80-IA of the Act.. the Tribunal had rightly computed the market value of electricity supplied by the captive power plants of the assessee to its industrial units after comparing it with the rate of power available in the open market, i. e., the price charged by the State Electricity Board while supplying electricity to industrial consumers. Therefore, the High Court was justified in deciding the appeal against the Department. The definition of the expression “market value” in the Explanation below sub-section (6) of section 80A of the Act was not applicable inasmuch as sub-section (6) was inserted in the statute with effect from April 1, 2009, much after the assessment year in question. ( AY.2001-02, 2006-07)