The concept of the "basic structure" of the Constitution of India was established through the landmark judgment in the Kesavananda Bharati case (1973) by the Supreme Court of India. In this case, the court held that the Parliament's power to amend the Constitution is not unlimited and that it cannot amend the basic structure of the Constitution. While the judgment did not provide an exhaustive list of what constitutes the basic structure, it did identify certain elements. Here are some of the key articles and principles that are generally considered to be part of the basic structure:

1. Preamble:
The Preamble of the Constitution sets out the ideals and objectives of the Constitution, including justice, liberty, equality, and fraternity. It is considered an integral part of the basic structure.

2. Fundamental Rights:
The Fundamental Rights enshrined in Part III of the Constitution, such as the right to equality, right to freedom of speech and expression, right to life and personal liberty, etc., are considered essential features of the basic structure.

3. Judicial Review:
The power of the judiciary to review and strike down laws that are inconsistent with the Constitution is considered a fundamental feature of the basic structure. It ensures the supremacy of the Constitution and protects individual rights.

4. Separation of Powers:
The principle of separation of powers, which divides the functions of the government into three branches (legislature, executive, and judiciary), is considered an essential feature of the basic structure.

5. Federalism:
The federal structure of the Indian Constitution, which provides for a division of powers between the central government and the states, is considered a vital part of the basic structure.

6. Rule of Law:
The principle of rule of law, which ensures that the government is bound by the law and that all individuals are equal before the law, is considered an integral part of the basic structure.

7. Parliamentary System:
The parliamentary form of government, with its emphasis on responsible government and collective responsibility of the executive to the legislature, is considered essential to the basic structure.

It is important to note that the list provided above is not exhaustive, and the concept of the basic structure remains flexible and subject to interpretation by the judiciary. The Supreme Court has the authority to determine what constitutes the basic structure of the Constitution on a case-by-case basis. The Kesavananda Bharati case reaffirmed the supremacy of the Constitution and established limitations on the amending power of the Parliament to protect the core principles and values of the Indian Constitution.