In August 1996, the DMK government under M. Karunanidhi set up a high-level committee to review educational standards.
Based on the committee’s recommendation, a Government Order (G.O.) was issued granting 15% reservation for students from panchayat schools in rural areas for professional courses.
In December 1997, the 15% reservation was extended to medical courses and later to law courses.
In 2001, the AIADMK government led by J. Jayalalithaa increased the rural quota from 15% to 25%.
In February 2002, a three-judge Bench of the Madras High Court struck down the G.O. as unconstitutional under Article 14 of the Indian Constitution.
The Tamil Nadu government filed a Special Leave Petition (SLP) in the Supreme Court challenging the High Court order.
The SLP argued that horizontal reservation aimed to support underprivileged rural students and was based on social and educational backwardness.
The Supreme Court declined to stay the Madras High Court’s judgment.
As a result, the 25% rural reservation policy was discontinued.
In September 2020, the AIADMK government under Edappadi K. Palaniswami passed a Bill for 7.5% horizontal reservation for government school students in NEET-based medical admissions.
The policy was based on recommendations from a Commission led by retired High Court judge P. Kalaiyarasan.
The Commission recommended a 10% reservation, but the government implemented 7.5%.
In August 2021, the DMK government under M. K. Stalin extended the 7.5% reservation to engineering, agriculture, veterinary, and fisheries courses.
This extension was based on recommendations from another Commission headed by retired High Court judge D. Murugesan.
The policy introduced a new criterion—socially and educationally deprived—without affecting the existing 69% vertical reservation.
Under the policy, government school students receive preferential admission across all vertical categories, including BC, MBC, SC, ST, and OC.
In April 2022, the Madras High Court upheld the constitutional validity of the 7.5% horizontal reservation.