Yes, Some states must be governed under special provision on the basis of historical, cultural, social requirements.

This is the most extra ordinary feature of the federal system. The special status pertain to North Eastern states (Nagaland, Assam, Mizoram etc).

Art 371-provides special provision to the nort eastern states largely due to a sizeable indigenous tribal population with a distinct history and culture, which they wish to retain.

Special provisions also exist for hilly States like Himachal Pradesh and some other

States like Andhra Pradesh, Goa, Gujarat, Maharashtra , Sikkim and Telangana.

Art 370-under this article special provision is provided to Jammu & Kashmir. Here, the central government has only limited powers and other powers listed in the Union List and Concurrent List can be used only with the consent of the State government

This has created resentment among other states as there is fear that these provision would lead to separation in those areas.This provision have not been able to stem alienation and the insurgency in parts of the region.

No this does not help in forging greater unity among the regions of the country, as the provision foster feeling of biasness among the states.