The Parliament is the supreme legislative body. It performs functions that may be categorized as follows: 

  1. Legislative Functions: Parliament is a law-making body. It legislates on the subjects mentioned in the Union List and the Concurrent List by the Constitution. If there is a clash between the Union government and the State government regarding any concurrent subject, the central law will prevail. Besides, if there is any subject not mentioned in any list, known as residuary subjects, it comes under the jurisdiction of the Parliament. An ordinary bill can be introduced in any of the two houses. If a bill is passed by the Lok Sabha, it is sent to Rajya Sabha which may pass the same or may suggest amendments in the bill. If the disagreement between the two Houses continues, it has to be resolved in a joint sitting of the two Houses. In the joint sitting, Lok Sabha has an upper hand with 550 members over the Rajya Sabha which has only a maximum of 250 members. To date, there have been only three ‘joint sittings’ of both the Houses. Once the bill is passed by both the Houses, it is sent to the President for his/ her assent and with his/her assent it becomes a law or an act. 
  2. Executive Functions: In a parliamentary system, there is a close relationship between the legislature and the executive. As discussed above, the real executive i.e. the Council of Ministers is collectively responsible to the Lok Sabha which can dislodge a ministry by passing a no-confidence motion against it. In 1999 Atal Bihari Vajpayee's government lost the confidence motion in the Lok Sabha and it resigned. However, both the Houses of Parliament maintain their control over the Council of Ministers through several other ways such as:
    1. By asking questions and supplementary questions: The first hour of every working day of Parliament relates to Question Hour in which the Ministers have to answer the questions raised by the members. 
    2. By discussing and passing motions: Calling Attention Motion, Adjournment Motion or Censure Motion can be moved and policies of the government can be debated and criticized.
    3. By expressing a lack of confidence: The Lok Sabha can express its lack of confidence in the executive by disapproving the budget or money bill or even an ordinary bill. 
  3. Financial Functions: The Parliament of India has been entrusted with the performance of important financial functions. It is the custodian of public money. It controls the entire purse of the Union government. It sanctions, from time to time, money to the government to enable it to run the administration effectively and successfully. The Parliament may pass, reduce or reject the demands for grants presented to it by the government. No taxes can be collected and no expenditure can be made without the approval of the Parliament. There are, however, certain limitations on the Rajya Sabha. These are: 
    1. a money bill cannot be introduced in the Rajya Sabha. 
    2. It has no power either to reject or amend a money bill. It can only make recommendations on the money bill. 
    3. If the Rajya Sabha along with its recommendations (if any) does not return it to Lok Sabha within 14 days, the bill is deemed to have been passed by both the Houses.
    4.  As regards the Annual Budget (Annual Financial Statement), it is presented in the Lok Sabha and the Rajya Sabha may only discuss it but can not stop it from becoming law. 
  4. Judicial Functions: The Parliament is empowered to prescribe the number of Judges of the Supreme Court by law. It is also authorized to establish a common High Court for two or more States as well as to constitute a High Court even for a Union Territory. A Chief Justice or Judge of the Supreme Court or of any High Court can be removed from his/her office by the President only after an impeachment process by both the Houses of Parliament. 

Miscellaneous Functions: The Parliament has the power to remove the President and the Vice President by a special majority of votes. This process is called Impeachment. It has the power to amend the Constitution. Certain parts of the Constitution can be amended by a simple majority and certain others require a two-thirds majority. Some other parts of the Constitution can be amended with a special majority of the Parliament and the approval of the Legislatures of half of the States.

Also readParliamentary Form Of Government In India

The Union Parliament - Lok Sabha And Rajya Sabha

Source NIOS