Under Section 121 of the Bharatiya Sakshya Adhiniyam, 2023 (corresponding to the former Section 115 of the Indian Evidence Act, 1872), when one person has, by his declaration, act or omission, intentionally caused or permitted another person to believe a thing to be true and to act upon such belief, then -

Section 121 of the BSA, 2023 embodies the rule of estoppel, carrying forward the former Section 115 of the Indian Evidence Act, 1872: when one person has, by his declaration, act or omission, intentionally caused or permitted another person to believe a thing to be true and to act upon such belief, neither he nor his representative shall be allowed, in any suit or proceeding between himself and such person or his representative, to deny the truth of that thing. Estoppel is a rule of evidence which prevents a person from contradicting his own representation on which another has acted to his detriment.