“12. What, in our view, emerges from these cases is that (1) where a suit under Section 72 of the Indian Contract Act will lie to recover moneys paid under mistake, a writ petition for refund of tax within the period of limitation prescribed under Article 96 of the Limitation Act, 1908, i.e., within 3 years, would also lie. But for filing of a writ petition to recover the money, unlike in a suit, the Supreme Court has restricted the starting point of limitation of 3 years to be from the date on which the judgment, declaring as void the particular law under which the tax was collected was rendered, and if any writ petition was filed beyond 3 years after that date, it will, the Supreme Court said, almost always be proper for the court to consider that it is unreasonable to entertain that petition for refund, though, even in cases where it was filed