How are the seats reserved for Scheduled Tribes determined until the re-adjustment under Article 170 takes place?
The seats reserved for Scheduled Tribes in the Legislative Assembly of a State (Arunachal Pradesh, Meghalaya, Mizoram and Nagaland) are determined until re-adjustment under Article 170 as follows:

(a) If all the seats in the existing Legislative Assembly are held by members of the Scheduled Tribes, then all the seats except one shall be reserved for the Scheduled Tribes.

(b) In any other case, such number of seats is reserved that bears a proportion not less than the number of members belonging to the Scheduled Tribes in the existing Assembly bears to the total number of seats in the existing Assembly.