Article 20 of Constitution of India and Protection in respect of conviction for offences

Article 20: Protection in respect of conviction for offences

• Article 20(1): 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 charged as an offence, nor be subjected to a penalty greater than that which might have been inflicted under the law in force at the time of the commission of the offence.
  
• Article 20(2): No person shall be prosecuted and punished for the same offence more than once.
  
• Article 20(3) No person accused of any offence shall be compelled to be a witness against himself.
  

This article embodies the fundamental principles of natural justice and provides protection against arbitrary and excessive punishment to any person who commits an offense.