Indian Penal Code, 1860
Section 246
repealedFraudulently or dishonestly diminishing weight or altering composition of coin
Whoever, fraudulently or dishonestly performs on any coin any operation which diminishes the weight or alters the composition of that coin, shall be punished with imprisonment of either description for a term which may extend to three years, and shall also be liable to fine.
Why this exists
A coin's value depends partly on its actual metal content and weight matching what the law specifies. Someone who shaves, files, dissolves, or otherwise alters a genuine coin to remove valuable metal (while still passing it off at full value) is defrauding whoever later accepts that coin. This section criminalises that kind of tampering with already-existing coin, separate from making counterfeit coin from scratch.