## Facts

- A public-interest petitioner from Assam challenged a statutory scheme applicable only in Assam for determining whether a person was an illegal migrant.
- The challenge targeted the Illegal Migrants (Determination by Tribunals) Act, 1983 and the Illegal Migrants (Determination by Tribunals) Rules, 1984, which created special tribunals and procedures for Assam.
- The petitioner alleged large-scale post-1971 illegal migration from Bangladesh into Assam, with claimed demographic and electoral effects and limited effective detection and deportation.
- Under the Foreigners Act, 1946 (generally applicable in India), the burden of proving one is not a foreigner lies on the person concerned; the Assam-specific scheme effectively placed the burden on the State/complainant and imposed procedural hurdles.
- The petitioner sought (i) invalidation of the Assam-only statute and rules, and (ii) application in Assam of the Foreigners Act, 1946 and the Foreigners (Tribunals) Order, 1964.

## Issues

1. Whether the Assam-only statutory scheme was arbitrary or unjustifiably discriminatory, violating the constitutional equality guarantee (Article 14), particularly when compared to the Foreigners Act framework.
2. Whether large-scale illegal migration could implicate the Union’s constitutional duty to protect a State from external aggression and internal disturbance (Article 355), and whether the Assam-only scheme impeded discharge of that duty.
3. Whether maintaining a more permissive and less effective determination procedure only for Assam lacked a rational basis under constitutional classification standards.

## Decision

- The Court struck down the Illegal Migrants (Determination by Tribunals) Act, 1983 and the 1984 Rules as unconstitutional.
- The Court held the Assam-only regime violated Article 14 because it imposed a materially different and less effective mechanism than the general foreigners law, without adequate justification.
- The Court treated sustained, large-scale illegal migration across an international border as a threat to the State and national security interests relevant to the Union’s Article 355 obligations.
- The Court directed that, for Assam, proceedings concerning foreigners would be governed by the Foreigners Act, 1946 and the Foreigners (Tribunals) Order, 1964, including the Foreigners Act’s burden-of-proof rule.

## Legal Principles

- A State-specific legal regime that is more permissive or less effective than the general law, without a rational and justifying basis, can constitute arbitrary discrimination prohibited by Article 14.
- Legislative and procedural design may be assessed by practical operation; a scheme that structurally prevents achievement of its stated object may be invalid as unreasonable and arbitrary.
- The Union’s duty to protect States from external aggression and internal disturbance (Article 355) can be implicated by sustained, large-scale illegal cross-border migration that threatens public order, governance, and security.
- In foreigners-determination proceedings, placing the burden of establishing lawful status on the person concerned (as under the general foreigners law) was treated as a valid and necessary evidentiary rule for effective enforcement.

## Conclusion

The Court invalidated Assam’s special tribunal-based migrant determination law and rules as arbitrary and discriminatory, held that large-scale illegal migration could trigger the Union’s protective duty toward a State, and required Assam to apply the general foreigners legal framework for identification and deportation.


Sarbananda Sonowal v. Union of India, (2005) 5 S.C.C. 665 (India 2005)