Section 29 Indian Evidence Act 1872
Section 29 of the Indian Evidence Act 1872 is about ‘Confession otherwise relevant not to become irrelevant because of promise of secrecy, etc’. It is under ‘ADMISSIONS’ of Chapter II of the Act. Chapter II is titled ‘OF THE RELEVANCY OF FACTS‘.
If such a confession is otherwise relevant, it does not become irrelevant merely because it was made under a promise of secrecy, or in consequence of a deception practiced on the accused person for the purpose of obtaining it, or when he was drunk, or because it was made in answer to questions which he need not have answered, whatever may have been the form of those questions, or because he was not warned that he was not bound to make such confession, and that evidence of it might be given against him.
See also:
Section 28 Indian Evidence Act 1872 (Confession made after removal of impression caused by inducement, threat or promise, relevant)
Section 30 Indian Evidence Act 1872 (Consideration of proved confession affecting person making it and others jointly under trial for same offence)