Duration of Rajya Sabha
The Rajya Sabha (first constituted in 1952) is a continuing chamber, that is, it is a permanent body and not subject to dissolution. However, one-third of its members retire every second year. Their seats are filled up by fresh elections and presidential nominations at the beginning of every third year. The retiring members are eligible for re-election and renomination any number of times.
The Constitution has not fixed the term of office of members of the Rajya Sabha and left it to the Parliament. Accordingly, the Parliament in the Representation of the People Act (1951) provided that the term of office of a member of the Rajya Sabha shall be six years. The act also empowered the president of India to curtail the term of members chosen in the first Rajya Sabha. In the first batch, it was decided by lottery as to who should retire. Further, the act also authorised the President to make provisions to govern the order of retirement of the members of the Rajya Sabha.
Duration of Lok Sabha
Unlike the Rajya Sabha, the Lok Sabha is not a continuing chamber. Its normal term is five years from the date of its first meeting after the general elections, after which it automatically dissolves. However, the President is authorised to dissolve the Lok Sabha at any time even before the completion of five years and this cannot be challenged in a court of law.
Further, the term of the Lok Sabha can be extended during the period of national emergency be a law of Parliament for one year at a time for any length of time. However, this extension cannot continue beyond a period of six months after the emergency has ceased to operate.