The Cabinet'Mission Plan for India envisaged a—

The Cabinet Mission Plan of 1946 proposed a three-tier administrative structure for India to preserve national unity while addressing regional autonomy [2]. At the apex, it recommended a 'Union of India' (Union of States) comprising both British Indian provinces and the Princely States [3]. This Union was to have jurisdiction over only three subjects: Foreign Affairs, Defence, and Communications, while all other powers and residuary subjects were vested in the provinces [3]. The plan specifically rejected the idea of a separate sovereign state of Pakistan, instead proposing a federal union where provinces could form groups (Groups A, B, and C) to manage common subjects [2]. This structure was designed as a 'two-tiered federal plan' or a 'Federal Union' to maintain a single independent constitutional entity [2]. Therefore, the plan envisaged a Union of States with a weak center and strong provincial autonomy.

Sources

1. [1] https://en.wikipedia.org/wiki/1946_Cabinet_Mission_to_India
2. [2] Modern India ,Bipin Chandra, History class XII (NCERT 1982 ed.)[Old NCERT] > Chapter 15: Struggle for Swaraj > Post-War Struggle > p. 304
3. [3] Introduction to the Constitution of India, D. D. Basu (26th ed.). > Chapter 4: OUTSTANDING FEATURES OF OUR CONSTITUTION > Incidents of Paramountey. > p. 51