Section 16(vi) in The Delhi Police (Punishment and Appeal) Rules, 1980
(vi)The accused officer shall, for the purpose of preparing his defence, be permitted to inspect and take extracts from such official documents as he may specify, provided that such permission may be refused for reasons to be recorded in writing, if in the opinion of the enquiry officer such records are not relevant for the purpose or against the public interest to allow him access thereto. The latest orders of the Government shall be applicable with regard to the charging of copying fees, etc.
