AB-PM-JAY was launched on 23 September 2018 and is implemented by the National Health Authority under the Ministry of Health and Family Welfare. Because health is a State subject and the scheme is delivered through State health agencies under a memorandum of understanding, participation has always been a State decision. West Bengal ran its own cashless scheme, Swasthya Sathi, and stayed outside the central scheme, becoming over the years the single remaining State or Union Territory not implementing it. The position changed in 2026: the National Health Authority and the State government signed a memorandum of understanding, making West Bengal the 36th State or UT in the scheme, and the actual rollout to beneficiaries followed on 16 August 2026. The State has chosen a layered design rather than a straight swap. AB-PM-JAY covers the families identified under central criteria, the new Mukhyamantri Swasthya Bima Yojana covers eligible residents who fall outside those criteria, and Swasthya Sathi continues for a transitional period so that patients mid-treatment and hospitals mid-empanelment are not stranded.

Two things make this more than a state-level administrative announcement. The first is completeness: a national health assurance scheme that one large State stood outside was national in name only, and portability, the ability of a migrant worker from one State to be treated in another on the same entitlement, only works if every State is inside the system. With West Bengal's entry the scheme reaches all 36 States and Union Territories. The second is the design of the transition. Running a central scheme, a new State scheme and the legacy scheme simultaneously for two to three months is unusual, and it addresses the real risk in any such switch, which is that a patient discovers at the hospital counter that the card in their hand is no longer the one the hospital accepts. For answers on cooperative federalism, this is a useful concrete example: health is a State subject, participation is negotiated through an MoU rather than mandated, and the State has retained its own scheme alongside the central one rather than being absorbed by it.