MAHABIR VEGETABLE OILS PVT. LTD. vs STATE OF HARYANA .

The Supreme Court addressed the applicability of promissory estoppel in the context of the Haryana General Sales Tax Act, 1973, particularly focusing on Section 64 and the retrospective effect of rules under Section 13B. The Court held that the State's promise of sales tax exemption for industries set up in backward areas must be honored, and the retrospective rules cannot adversely affect the rights of the industries that relied on the initial policy. The judgment affirmed the principle that the government is bound by its promises made to encourage industrial development.