Discuss the constitutional and jurisprudential basis for sub-classification of Scheduled Castes and Scheduled Tribes as laid down in *State of Punjab v. Davinder Singh* (2024). How does it differ from the creamy layer principle applicable to OBCs?

Sub-classification means dividing the Scheduled Caste/Scheduled Tribe lists into sub-groups so that quota benefits reach the most deprived within them. In State of Punjab v. Davinder Singh (2024), a seven-judge Bench upheld this power, advancing substantive equality.

Constitutional basis

• Article 14 permits reasonable classification; the Court held historical and empirical evidence shows SCs/STs are not a homogenous class, so a "class within a class" is valid [1].
• Articles 15(4) and 16(4) empower the State to make special provisions for backward classes; prioritising the most backward furthers, rather than dilutes, this mandate.
• Articles 341/342 remain untouched — states may only re-order preference within the Presidential list, not add to or delete from it.
• Safeguards: sub-classification must rest on empirical data of inadequate representation, and no sub-class may be given 100% of the quota [1].
• States have begun operationalising this, as with the Karnataka Scheduled Castes (Sub-classification) Bill, 2025 [4].

Jurisprudential basis

• By 6:1, the Bench overruled E.V. Chinnaiah (2004), which had treated SCs as homogenous and barred sub-classification [1].
• Reservation was read as a means to correct graded backwardness, since the least advanced sub-castes were being crowded out by relatively better-placed ones [1].

Distinction from the OBC creamy layer

• Purpose: sub-classification redistributes quota among sub-groups, excluding no one; creamy layer excludes advanced individuals from benefits altogether.
• Unit and criterion: creamy layer is individual and status/income-based — the DoPT Office Memorandum of 1993 and the ₹8 lakh income ceiling [2][3]; sub-classification is group-based on backwardness data.
• Source: creamy layer flows from Indra Sawhney (1992), confined to OBCs; the Centre maintains it is inapplicable to SCs/STs, whose disadvantage stems from untouchability, not income [5].

Davinder Singh thus targets affirmative action inward without narrowing its constituency. Going forward, states should build reliable caste-wise socio-economic data so sub-quotas survive judicial scrutiny, fulfilling the Constitution's promise of equality of opportunity for the most marginalised.