Autonomous District Councils lack legislative competence to enact anti-defection laws under the Sixth Schedule.

The petitioners, residents of Dima Hasao district, challenged the constitutional validity of the "Constitution of N.C. Hills Autonomous Council (42nd Amendment) Act, 2017".

This amendment inserted Rule 18A into the principal rules, providing for the disqualification of elected members of the Council on grounds of defection/anti-defection, mirroring the Tenth Schedule of the Constitution of India.

The N.C. Hills Autonomous Council (NCHAC) was established under the Sixth Schedule of the Constitution.

The petitioners contended that the Council exceeded its legislative competence as the Sixth Schedule does not empower it to legislate on anti-defection.

1. Whether the N.C. Hills Autonomous Council has the legislative competence under the Sixth Schedule of the Constitution to frame laws regarding disqualification on the ground of defection.

2. Whether the impugned Rule 18A can be sustained by applying the doctrine of pith and substance in relation to the power to set "qualifications" for election.

3. Whether the impugned law is inconsistent with the constitutional scheme and the Tenth Schedule of the Constitution.

Paragraphs 2(6) and 2(7) of the Sixth Schedule of the Constitution, which enumerate the specific subjects—such as qualifications for being elected and conduct of business—on which the Governor or District Councils may make rules.

Paragraphs 3 and 3A, which list the specific legislative subjects assigned to Autonomous Councils.

The Tenth Schedule of the Constitution, which serves as a complete code for anti-defection.

Principle from District Council of United Khasi and Jayantia Hills v. Sitimon Sawian, establishing that Autonomous Councils have limited, enumerated powers rather than plenary legislative authority.

The court reasoned that unlike Parliament or State Legislatures, Autonomous District Councils are not sovereign legislatures and possess only limited, enumerated powers.

Although the State argued that the power to set "qualifications" under Paragraph 2(6)(d) includes the power to legislate on "disqualification" via the doctrine of pith and substance, the court rejected this, holding that anti-defection is a substantive constitutional matter, not a procedural or incidental one.

The court observed that the Sixth Schedule requires a formal Parliamentary amendment under Paragraph 21 to alter the tenure or core functionality of Council members.

The court noted that the pendency of the Constitution (125th Amendment) Bill, 2019, in the Rajya Sabha—which intends to grant Councils the power to legislate on defection—demonstrates that such power does not currently exist.

Because the Council lacks plenary power, it cannot "incidentally" encroach upon a field (anti-defection) that is already occupied by the Tenth Schedule.

Rule 18A, introduced by the 42nd Amendment Act of 2017, was declared ultra vires, unconstitutional, and null and void.

The court struck down the legislation and allowed the writ petition.