India's residential real estate sector is undergoing a structural market bifurcation that has accelerated dramatically since 2020: a sustained and rapid shift in both supply and demand toward premium and luxury housing, at the direct expense of affordable and mid-segment stock. This paper examines the premiumisation of the Delhi National Capital Region's (NCR) housing market as the most advanced case of this phenomenon in India. Drawing on longitudinal market data (2018–2025) from JLL, ANAROCK, Knight Frank, and Cushman & Wakefield, and applying a multi-level analytical framework integrating Housing Financialisation Theory, Urban Political Economy, and Producer-Consumer Demand Theory, the study identifies and quantifies four interlocking structural drivers of premiumisation: (i) developer margin arbitrage that makes premium projects financially dominant over affordable alternatives; (ii) demand-side wealth concentration among HNIs, GCC professionals, and NRIs; (iii) institutional capital flows amplifying the premium segment; and (iv) a policy vacuum created by the withdrawal of demand-side subsidies and the absence of mandatory supply-side inclusionary requirements. Empirically, the paper documents a collapse in the affordable housing launch share from 52.4% in 2018 to 17% by H1 2025, a 72% appreciation in luxury prices in Delhi NCR between 2022 and 2025, and a supply-to-demand ratio in affordable housing of 0.36 in 2025, down from 1.05 in 2019. Through a structured Policy Response Matrix, the paper evaluates the adequacy of existing instruments — PMAY-U 2.0, RERA, GST concessions, and the DDA model — and finds each insufficient in isolation. The paper concludes with an integrated policy prescription centered on mandatory inclusionary zoning, a revived Credit Linked Subsidy Scheme, and a developer cross-subsidisation framework.