Article-20 of the Constitutiongrants protection against arbitrary and excessive punishment to an accused person. It contains three provisions in that direction No Ex-post-facto Law No person shall be convicted of any offence except for violation of a law in force at the time of the commission of the Act nor subjected to a penalty greater than that prescribed by the law in force at the time ofthe commission of the Act.No Double Jeopardy No person shall be prosecuted and punished for the same offence more than once.No Self-incrimination No person accused of any offence shall be compelled to be a witness against himself.As per the Constitution, a person/entity can be tried retrospectively in certain instances as provided by the law
