Which one of the following statements about the constitutional position of the States in India and the National Capital Territory of Delhi is not correct?

Introduction / Context:
This question examines your understanding of the federal structure of India, the special position of the former State of Jammu and Kashmir, and the constitutional status of the National Capital Territory of Delhi. It asks you to identify which statement about these constitutional arrangements is not correct. Knowledge of provisions relating to State Constitutions, secession, and the size of the Council of Ministers in Delhi is required to answer correctly.

Given Data / Assumptions:
- Statement A refers to States in India and the special case of the former State of Jammu and Kashmir having had its own Constitution.
- Statement B explicitly mentions that Jammu and Kashmir had its own Constitution before the abrogation of Article 370 in 2019.
- Statement C concerns the right of States to secede from the Union of India.
- Statement D refers to the maximum size of the Council of Ministers in the National Capital Territory of Delhi, expressed as a percentage of the total number of members in the Legislative Assembly.
- The task is to determine which one of these statements is not in accordance with constitutional provisions.

Concept / Approach:
India has a federal structure with a strong unitary bias. Most States do not have separate Constitutions and follow the Constitution of India. Historically, Jammu and Kashmir had a special status under Article 370 and had its own Constitution until that special status was removed in 2019. No State in India has a constitutional right to secede from the Union. The size of Councils of Ministers is generally governed by the 91st Constitutional Amendment Act, which prescribes a ceiling of 15 percent of the strength of the Legislative Assembly for States, but the National Capital Territory of Delhi has a special provision that fixes a different ceiling. Therefore, we need to check each statement against these specifics to identify the incorrect one.

Step-by-Step Solution:
Step 1: Statement A says that, except for the former State of Jammu and Kashmir, States in India cannot have their own separate Constitutions. This reflects the reality that almost all States operate under the single Constitution of India and that, historically, only Jammu and Kashmir had its own separate Constitution, making the statement substantively correct. Step 2: Statement B notes that the erstwhile State of Jammu and Kashmir had its own Constitution before the abrogation of Article 370 in 2019. This is factually correct, as Jammu and Kashmir had a separate Constitution adopted in 1957 which remained in force until the special status was removed. Step 3: Statement C notes that States in India do not have the right to secede from the Union of India. This aligns with the constitutional scheme, which does not grant any unilateral right of secession to any State. Step 4: Statement D claims that the maximum number of members in the Council of Ministers of the National Capital Territory of Delhi can be 15 percent of the total number of members in the Legislative Assembly. However, Article 239AA and related provisions specify that the Council of Ministers in Delhi shall not exceed a smaller percentage, commonly understood to be about 10 percent, rather than the 15 percent limit that applies to States under the 91st Amendment. Step 5: Since Statements A, B and C are correct and Statement D misstates the ceiling for the size of the Council of Ministers in Delhi, Statement D is the one that is not correct.

Verification / Alternative check:
For verification, recall that the 91st Constitutional Amendment Act fixes the maximum size of the Council of Ministers in States at 15 percent of the total number of members of the Legislative Assembly, subject to a minimum of twelve members. The National Capital Territory of Delhi, however, is governed by Article 239AA, which provides that the Council of Ministers shall consist of not more than a smaller percentage of the Assembly strength. Standard polity references consistently point out this difference between States and the National Capital Territory of Delhi. Therefore it is clear that applying the 15 percent limit to Delhi is incorrect, confirming Statement D as the wrong statement.

Why Other Options Are Wrong:
Option A is describing the general rule that States in India, other than the historically special case of Jammu and Kashmir, do not have their own Constitutions, which is accurate.
Option B correctly recognises that the erstwhile State of Jammu and Kashmir had its own Constitution before the removal of its special status in 2019.
Option C correctly captures the constitutional reality that no State in India has the right to secede from the Union, reflecting the indestructible nature of the Union in Indian federalism.

Common Pitfalls:
A frequent pitfall is to assume that the same 15 percent ceiling for the size of the Council of Ministers applies uniformly to all States and to the National Capital Territory of Delhi, without noticing the special provision for Delhi. Another error is to overlook the historical special status of Jammu and Kashmir and to assume that no State ever had its own Constitution, which would make both Statement A and Statement B suspect. Candidates should carefully distinguish between regular States, Union Territories with legislatures and special cases created by specific constitutional provisions. Paying attention to special articles such as Article 370 and Article 239AA helps prevent such mistakes.

Final Answer:
The incorrect statement is The maximum number of members in the Council of Ministers of the National Capital Territory of Delhi can be 15 percent of the total number of members in the Legislative Assembly.