Section 91(5)(c) in The Indian Post Office Rules, 1933
(c)where the insured article has been delivered to the addressee, or where the article is returned to the sender and the addressee or sender, as the case may be, has signed and returned the receipt therefor without protest, or in the case of an insured letter, without immediately making a complaint of abstraction of or damage to the contents of the letter to the administration of the office which delivered the article and proving that the abstraction or damage took place before the delivery of the letter;