The decision to adopt a single, common citizenship for all Indians, rather than state-based citizenships, was a significant and deliberate choice during the framing of the Indian Constitution. Here are the key considerations and debates surrounding this decision:

Considerations for a Single, Common Citizenship
National Unity: A primary consideration was to foster a sense of national unity and integration. Given India’s vast diversity in terms of languages, cultures, and religions, a common citizenship was seen as a way to unite the country and strengthen national identity.

Equality and Non-discrimination: A single citizenship ensures equal treatment of all citizens, regardless of the state in which they reside. This prevents discrimination based on state affiliation and promotes a sense of equality among all Indians.

Simplification of Legal and Administrative Processes: Having a single citizenship simplifies legal and administrative processes. It eliminates the complexities and potential conflicts that could arise from multiple layers of citizenship and the corresponding legal rights and responsibilities.

Mobility and Economic Integration: A common citizenship facilitates free movement of people across state borders, which is essential for economic integration and growth. It allows individuals to live, work, and conduct business anywhere in the country without facing state-based restrictions.

Debates and Considerations Against State-based Citizenship
Federal Autonomy: Critics of single citizenship argued that it could undermine the federal structure and the autonomy of states. They feared that centralization could erode the powers and identities of individual states.

Diverse Identities: India’s states often have distinct linguistic and cultural identities. There were concerns that a single citizenship might not adequately respect or represent these diverse identities, leading to feelings of marginalization.

Precedents from Other Countries: Some pointed to federal systems like the United States, where dual citizenship (state and federal) exists. They argued that state-based citizenship could enhance federalism by giving states more control over their affairs and the rights of their residents.

Resolution and Final Decision
Debates in the Constituent Assembly: During the Constituent Assembly debates, proponents of single citizenship, including Dr. B.R. Ambedkar, argued strongly for its necessity in maintaining national unity and preventing divisive regionalism. They emphasized the importance of having a unified nation where citizens are treated equally across all states.

Balance of Federal and Unitary Features: The framers of the Constitution sought to balance federal and unitary features. While they opted for single citizenship, they also provided significant powers to the states and established a federal structure to ensure decentralization and respect for regional diversity.

Acceptance of Diversity within Unity: The decision reflected an acceptance of India’s diversity within a framework of unity. The Constitution recognizes and protects linguistic, cultural, and regional identities through various provisions, while ensuring that all citizens have the same national identity and rights.

Conclusion
The choice of a single, common citizenship for all Indians was a conscious effort to build a cohesive and integrated nation-state. It aimed to foster national unity, ensure equality, simplify legal frameworks, and facilitate economic integration, while also balancing the need for federal autonomy and respect for regional identities. This decision remains a cornerstone of India’s constitutional framework, reflecting the country’s commitment to unity in diversity.