Why Nagaland has no income tax?

Tax exemption to tribes

Nagas, like all resident tribes of the sixth schedule areas of the Northeast, are exempt from paying income tax. The tribals of five north-eastern states – Tripura, Manipur, Mizoram, Nagaland and Arunachal Pradesh – are fully exempted from tax under Section 10 (26) of the Income Tax Act, 1961