Your question is too general and vague. It depends on the RTI reply concerned and its contents and the facts of the case. Some RTI replies may be admissible in evidence while some others may not be.
If the RTI reply encloses any document with it, such document may be admissible in evidence if it relates to some relevant facts under the provisions of the Evidence Act. In some specific situations, the RTI reply may itself be considered as a document and may be admissible if it is relevant.
No general answer can be given to your question. It depends on the facts of each case. Likewise, whether it would be admissible as secondary or primary evidence, would again depend on facts of the case concerned. For example, if the RTI reply itself is considered as a document, it may be primary evidence of itself, being the original document.
Section 20 of the Right to Information Act provides for penalty to be imposed on the concerned Public Information Officer, inter alia, for knowingly giving incorrect, incomplete or misleading information. If no penalty is imposed for this, then the remedy is to file, may be, a writ petition before the High Court for suitable action in the matter. Perhaps, a complaint may also be made to the higher officers of the department concerned for a disciplinary action.
Dr. Ashok Dhamija is a New Delhi based Supreme Court Advocate and author of law books. Read more about him by clicking here. List of his Forum Replies. List of his other articles. List of his Quora Answers. List of his YouTube Videos.