The OBC issue becoming a regional affair pursued at the state level instead of the central level occurred in the mid-fifties.

Explanation:

1. Introduction:
- The OBC issue refers to the question of reservation for Other Backward Classes (OBCs) in educational institutions and government jobs in India.
- Initially, the issue was dealt with at the central level, but it later became a regional affair pursued at the state level.

2. Central level involvement:
- In the early years after India's independence in 1947, the issue of OBC reservation was primarily addressed by the central government.
- The First Backward Classes Commission, also known as the Kalelkar Commission, was appointed by the central government in 1953 to identify socially and educationally backward classes and suggest measures for their advancement.
- The commission submitted its report in 1955, which led to the central government implementing reservation policies for OBCs in central educational institutions and government jobs.

3. Shift to state level:
- However, in the mid-fifties, the OBC issue started to be pursued at the state level rather than the central level.
- This shift occurred due to the varying social, economic, and political contexts of different states in India.
- Each state had its own set of backward classes, and the demand for OBC reservation differed across states.
- The state governments started to take up the cause of OBC reservation based on the specific requirements and demands of their respective states.

4. State-level initiatives:
- Various state governments began conducting their own surveys and commissions to identify the backward classes within their jurisdictions.
- They formulated their own reservation policies and implemented them in state educational institutions and government jobs.
- These state-level initiatives allowed for a more localized approach to addressing the OBC issue, taking into account the unique socio-economic conditions of each state.

5. Conclusion:
- In summary, the OBC issue started as a central-level concern in the mid-forties, with the central government implementing reservation policies.
- However, in the mid-fifties, the issue shifted to the state level, where different states pursued their own initiatives and policies to address the backwardness of OBCs.
- This regionalization of the OBC issue at the state level allowed for a more nuanced and context-specific approach to reservation policies.