“20. It is important to note that the regulatory powers of the Central Commission, so far as tariff is concerned, are specifically mentioned in Section 79(1). This regulatory power is a general one, and it is very difficult to state that when the Commission adopts tariff under Section 63, it functions de hors its general regulatory power under Section 79(1)(b). For one thing, such regulation takes place under the Central Government’s guidelines. For another, in a situation where there are no guidelines or in a situation which is not covered by the guidelines, can it be said that the Commission’s power to “regulate” tariff is completely done away with? According to us, this is not a correct way of reading the aforesaid statutory provisions. The first rule of statutory interpretation is that the statute must be read as a whole. As a concomitant of that rule, it is also clear that all the discordant notes struck by the various Sections must be harmonized. Considering the fact that the non-obstante clause advisedly restricts itself to Section 62, we see no good reason to put Section 79 out of the way altogether. The reason why Section 62 alone has been put out of the way is that determination of tariff can take place in one of two ways – either under Section 62, where the Commission itself determines the tariff in accordance with the provisions of the Act, (after laying down the terms and conditions for determination of tariff mentioned in Section 61) or under Section 63 where the Commission adopts tariff that is already determined by a transparent process of bidding. In either case, the general regulatory power of the Commission under Section 79(1)(b) is the source of the power to regulate, which includes the power to determine or adopt tariff. In fact, Sections 62 and 63 deal with “determination” of tariff, which is part of “regulating” tariff. Whereas “determining” tariff for inter-State transmission of electricity is dealt with by Section 79(1)(d), Section 79(1)(b) is a wider source of power to “regulate” tariff. It is clear that in a situation where the guidelines issued by the Central Government under Section 63 cover the situation, the Central Commission is bound by those guidelines and must exercise its regulatory functions, albeit under Section 79(1)(b), only in
