For an employee covered under the Payment of Gratuity Act who receives ₹30,00,000 as gratuity due to death or physical disability, what is the maximum exemption available under Section 10(10) of the Income-tax Act? Is the exemption limited to ₹20,00,000 or is any higher exemption available in such cases? Does the exemption amount differ between the Old Tax Regime and New Tax Regime?