Articles 1 to 4 under Part I of the Constitution describe the Union and its Territory.
Article 1 (1) states that India, that is Bharat, shall be a Union of States.
Article 1 (2) states that the States and the territories thereof shall be as specified in the First Schedule.
Article 1 (3) states that the territory of India shall comprise:
the territories of the States;
the Union territories specified in the First Schedule; and
Such other territories as may be acquired.
There are a total of 29 States, 6 Union Territories, and 1 National Capital Territory (as shown in the map given above).
Article 2 states that the Parliament may by law admit into the Union, or establish new States on such terms and conditions as it thinks fit.
Article 3 states that the Parliament may by law form a new State by separation of a territory from any State or by uniting two or more States or parts of States or by uniting any territory to a part of any State.
Article 4 states that any law referred to in Article 2 or Article 3 shall contain such provisions for the amendment of the First Schedule and the Fourth Schedule as may be necessary to give effect to the provisions of the law and may also contain such supplemental, incidental, and consequential provisions (including provisions as to representation in Parliament and in the Legislature or Legislatures of the State or States affected by such law) as the Parliament may deem necessary.