Article 3 of Constitution of India "Formation of new States and alteration of areas, boundaries or names of existing States"
Parliament may by law.
(a) form a new State by separation of 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;
(b) increase the area of any State;
(c) diminish the area of any State;
(d) alter the boundaries of any State;
(e) alter the name of any State;
Provided that no Bill for the purpose shall be introduced in
either House of Parliament except on the recommendation of
the President and unless, where the proposal contained in
the Bill affects the area, boundaries or name of any of the
States, the Bill has been referred by the President to the
Legislature of that State for expressing its views thereon
within such period as may be specified in the reference or
within such further period as the President may allow and
the period so specified or allowed has expired.
Explanation I - In this Article, in clauses (a) to (e),
"State" includes a Union territory, but in the proviso,
"State" does not include a Union territory.
Explanation II - The power conferred on Parliament by clause
(a) includes the power to form a new State or Union
territory by uniting a part of any State or Union territory
to any other State or Union territory.