Promissory estoppel in tax exemption claims fails where only preliminary steps were taken before the revised scheme took effect.

Promissory estoppel against the Government applies only where an assessee has substantially and irretrievably altered position in reliance on a tax exemption promise before the scheme is withdrawn. Mere preliminary steps, such as tenancy arrangements and machinery orders, were insufficient here, and production began only after the amended exemption scheme took effect. The statutory restructuring of the sales tax exemption scheme therefore prevailed, and the applicants could not claim an eligibility certificate on the basis of the earlier rule.

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Issues: Whether the applicants were entitled to eligibility certificate for sales tax exemption on the basis of promissory estoppel, and whether the amended exemption scheme could be enforced against them.

Analysis: The exemption under the sales tax rules was embodied in statutory rules made under the parent Act and the later notification substituted a revised scheme with a cut-off date for commencing production. Promissory estoppel could apply against governmental action in appropriate cases, but only where the promisee had altered position substantially and irretrievably in reliance on the promise before the scheme changed. The applicants had only taken preliminary steps such as tenancy arrangements and machinery orders, while actual production began much later, after the amended scheme had come into force. The materials did not establish that the project had been undertaken or construction had started in the relevant sense before the change in the law, nor that the applicants had suffered an irretrievable alteration of position on the strength of the earlier exemption.

Conclusion: The applicants were not entitled to invoke promissory estoppel to claim exemption under the earlier rule, and they could not obtain eligibility certificate on that basis.

Final Conclusion: The statutory withdrawal and restructuring of the tax exemption scheme prevailed, and the applications for relief failed.

Ratio Decidendi: Promissory estoppel against the Government is available only when a promisee, acting in reliance on a governmental promise, has substantially and irretrievably altered position before the scheme is withdrawn; mere preliminary steps do not suffice, especially where production commences only after the revised statutory scheme takes effect.

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