S. 35AC : Expenditure on eligible projects-Schemes–Promissory estoppel is not available to an assessee against the exercise of legislative power nor any vested right accrues to an assessee in the matter of grant of any tax concession to him-In a taxing statute, a plea based on equity or/and hardship is not legally sustainable-Withdrawal of exemption is valid. S. 35AC(7) is prospective in nature-Provision is valid in law. [S. 35AC(7), Art. 142, 226]