when can a president call a special session of congress
Special session This power exists for urgent or extraordinary situations that require congressional action when Congress is adjourned. Presidents have exercised this power 46 times to recall only the Senate and 28 times to recall both Chambers of Congress, most recently by Harry Truman in 1948.[2]
Article One of the United States Constitution Section Two provides for the election of the House of Representatives every second year. Since Representatives are to be "chosen... by the People," State Governors are not allowed to appoint temporary replacements when vacancies occur in a state's delegation to the House of Representatives; instead, the Governor of the state is required by clause 4 to issue a writ of election calling a special election to fill the vacancy.
United States House of Representatives The United States House of Representatives is the lower chamber of the United States Congress. The Senate is the upper chamber. Together they compose the legislature of the United States.
President of India Governors of States are also appointed by the President who shall work at the pleasure of the President. Per Article 156, President is empowered to dismiss a governor who has violated the constitution in his acts.