Know Inner Line Permit and its applicable:

• A British-era system, the ILP is a travel document Indian citizens need to possess to enter the frontier States of north-eastern India: Aruanchal Pradesh, Mizoram and Nagaland.
• It is issued under the Bengal Eastern Frontier Regulation, 1873, to regulate the movement of people who do not belong to these States.
• The ILP is valid for a week, but can be extended.
• People who frequent these States for work can opt for a special ILP renewable annually.
• Since the ILP is mandatory for Indians and the Protected Area Permit for foreigners, the fact that the labourers ejected from Arunachal Pradesh did not possess the permit put their nationality under a cloud.

Source:TH