The judgment addresses challenges to state laws that sub-classify Scheduled Castes for reservation purposes, examining constitutional permissibility under Articles 14, 15, and 16, and whether such sub-classification violates Article 341(2) by altering the Presidential List (!) .

The case involves multiple appeals and writ petitions from states like Punjab, Haryana, and Tamil Nadu, questioning the validity of sub-classification within Scheduled Castes for affirmative action in education and public employment (!) .

Historical context traces "Scheduled Castes" from "depressed classes" under the 1935 Act, emphasizing untouchability and social disabilities as the basis for identification, with varying degrees of discrimination across regions (!) .

The 1936 Order and 1950 Order under Articles 341 and 342 specify castes, races, or tribes as Scheduled Castes, forming the basis for reservations, with Parliament alone empowered to modify the lists (!) .

Article 341 creates a deeming fiction where notified castes are regarded as Scheduled Castes for constitutional purposes, but does not imply homogeneity; sub-classification is permissible if it addresses inter-se backwardness without excluding any group (!) .

Sub-classification under Articles 15(4) and 16(4) is allowed if based on intelligible differentia like social backwardness and inadequate representation, aligning with substantive equality (!) .

The Court overrules prior precedent holding sub-classification impermissible, affirming that Scheduled Castes are heterogeneous, allowing states to provide preferential treatment to more backward sub-groups (!) .

Historical evidence from censuses and reports shows Scheduled Castes suffer varying degrees of untouchability and social exclusion, justifying sub-classification for equitable distribution of benefits (!) .

Empirical studies indicate intra-group discrimination within Scheduled Castes, such as denial of access to shared resources among sub-castes, supporting the need for targeted affirmative action (!) .

States can sub-classify if data shows inadequate representation of certain sub-groups, but must ensure no total exclusion from benefits, using models like preference or exclusive quotas within limits (!) .

Judicial review requires states to provide quantifiable data on backwardness and representation; sub-classification must not breach the 50% reservation ceiling or perpetuate inequality (!) .

Article 335 mandates considering Scheduled Castes' claims in services while maintaining efficiency, interpreted as promoting inclusion rather than limiting reservations (!) .

The creamy layer principle applies to Scheduled Castes and Tribes to exclude advanced members, ensuring benefits reach the truly disadvantaged, without altering the Presidential List (!) .

Sub-classification advances substantive equality by addressing intra-group disparities, but must be evidence-based to avoid arbitrariness (!) .