The Sixth Schedule to the Constitution of India provides measures of autonomy and self-governance to the Scheduled Tribes in the hill regions of Northeast India.
During the British Raj, the frontier regions of the Assam province populated by tribal communities were designated as "excluded areas" or "partially excluded areas". The North-East Frontier Tracts (present-day Arunachal Pradesh), the Naga Hills district (present-day Nagaland) and the Lushai Hills district (present-day Mizoram) were designated as "excluded areas", while the Khasi and Jaintia Hills region (in present-day Meghalaya) was designated as a "partially excluded area". The "exclusion" worked in both directions. The tribes were excluded from the legislature and the governance mechanisms of the Assam province. At the same time, the laws created for the province were excluded from application to the tribal areas. Essentially, the tribes governed themselves via their traditional systems, except for being asked to participate in the imperial interests such as taxation and road-building.
During the formulation of the Constitution of India, the Sixth Schedule was devised to continue these modes of governance, providing the tribes autonomy and to allow them to continue their own traditional systems of self-governance. The tribal areas in other parts of India were covered by a parallel Fifth Schedule with somewhat weaker forms of autonomy. The difference was justified by B. R. Ambedkar in the following words:
Autonomous district councils were granted under the Sixth Schedule to the following regions in the-then Assam state:
The 'Part A' regions were considered more developed and where democratic institutions could function, while 'Part B' regions were considered to be still in primitive stages at the time of establishment of the Indian constitution. The latter were administered under the discretionary powers of the Governor of Assam. Manipur and Tripura, having been princely states separate from the province of Assam, did not obtain the benefit of the Sixth Schedule, even though similar considerations might have applied to them.
When Naga Hills and Lushai Hills became independent states of India (as Nagaland and Mizoram respectively), these provisions became redundant for the states as a whole. However minority tribal districts in these states were granted the Sixth Schedule provisions in course of time. The North-East Frontier Tracts also became the independent state of Arunachal Pradesh. When Meghalaya was carved out of Assam, the Garo Hills, Khasi Hills and Jaintia Hills retained their Sixth Schedule status.
The state of Tripura formed an autonomous district council for its tribal areas in 1982 and requested that they be brought under the Sixth Schedule, which was granted in 1984.
There are 10 Sixth Schedule districts in India.