Constitution of India, 1949
83. Duration of Houses of Parliament.-
(1) The council of States shall not be subject to dissolution, but as nearly as possible one-third of the members thereof shall retire as soon as may be on the expiration of every second year in accordance with the provisions made in that behalf by Parliament by law.
(2) The House of the People, unless sooner dissolved, shall continue for five years from the date appointed for its first meeting and no longer and the expiration of the said period of five years shall operate as a dissolution of the House: Provided that the said period may, while a Proclamation of Emergency is in operation, be extended by Parliament by law for a period not exceeding one year as a time and not extending in any case beyond a period of six months after s the Proclamation has ceased to operate.