India is unitary State justify

According to D.D. Basu, “The Constitution of India is neither purely federal nor purely unitary but it is a combination of both." Similarly, B.N. Banerjee has said that, "The Constitution of India is federal in form but unitary in spirit." In fact the Constitution of India has many federal features as well as unitary features. The brief description of both is given below:
1. Written and Rigid Constitution: The Constitution of India is written and rigid. The powers of the Central Government and State Governments, Fundamental Rights and Directive Principles of State Policy have been clearly defined in the Constitution and there is very little possibility of conflict. The Constitution is rigid also since most of its provisions cannot be changed by a simple majority of Parliament. The ratification of at least fifty percent States is also required for the purpose. Thus, the Centre cannot make arbitrary changes in the Constitution.
2. Supremacy of the Constitution: The Indian Constitution is the supreme law of the country. No individual, institution, functionary of the government or even government can work against the provisions of the Constitution. Both the Central Government and the Governments of the States will run the administration in accordance with the provisions of the Constitution. If parliament or any state Legislature passes a law in contravance of the provisions of the Constitution that can be declared unconstitutional by the Supreme Court. That is why all the high officials of the country— President, Vice-President, Ministers, Judges of Supreme Court and High Courts—while assuming office, take an oath to abide by the Constitution and accept this supremacy of the Constitution.