Once a pardon is given, the person can never be tried again, no matter what.

The pardon is conditional; if the Public Prosecutor certifies that the person concealed facts or gave false evidence, they can be tried again for the original offence and for perjury, subject to safeguards like a fair hearing on whether they actually complied.

Bharatiya Nagarik Suraksha Sanhita, 2023

Section 345

Trial of person not complying with conditions of pardon

(1) Where, in regard to a person who has accepted a tender of pardon made under section 343 or section 344, the Public Prosecutor certifies that in his opinion such person has, either by wilfully concealing anything essential or by giving false evidence, not complied with the condition on which the tender was made, such person may be tried for the offence in respect of which the pardon was so tendered or for any other offence of which he appears to have been guilty in connection with the same matter, and also for the offence of giving false evidence: Provided that such person shall not be tried jointly with any of the other accused: Provided further that such person shall not be tried for the offence of giving false evidence except with the sanction of the High Court, and nothing contained in section 215 or section 379 shall apply to that offence.§

(2) Any statement made by such person accepting the tender of pardon and recorded by a Magistrate under section 183 or by a Court under sub-section (4) of section 343 may be given in evidence against him at such trial.§

(3) At such trial, the accused shall be entitled to plead that he has complied with the condition upon which such tender was made; in which case it shall be for the prosecution to prove that the condition has not been complied with.§

(4) At such trial, the Court shall—§

(a) if it is a Court of Session, before the charge is read out and explained to the accused;§

(b) if it is the Court of a Magistrate, before the evidence of the witnesses for the prosecution is taken, ask the accused whether he pleads that he has complied with the conditions on which the tender of pardon was made.§

(5) If the accused does so plead, the Court shall record the plea and proceed with the trial and it shall, before passing judgment in the case, find whether or not the accused has complied with the conditions of the pardon, and, if it finds that he has so complied, it shall, notwithstanding anything contained in this Sanhita, pass judgment of acquittal.§

Why this exists

This provision protects the integrity of the pardon system: it makes clear that the immunity granted to an approver is not unconditional, and that anyone who breaks their word by concealing facts or lying can still be prosecuted, both for the original crime and for perjury, so the deal remains a genuine incentive for truth-telling rather than a free pass to lie.

Common misconceptions

Myth: Once a pardon is given, the person can never be tried again, no matter what.
Fact: The pardon is conditional; if the Public Prosecutor certifies that the person concealed facts or gave false evidence, they can be tried again for the original offence and for perjury, subject to safeguards like a fair hearing on whether they actually complied.