Indian is a group with a mutated form of R1A1 Z93(not same as the slavic version) derived from the central asian r1a1. And Indians also has a significant portion of African L2,along with middle eastern J gene. India is a race newly formed by african+ central asian+middle eastern that evolved in the harsh climatic condition of South Asia.
Kind of different case than the NE region ,which has historical notion even in folk songs about the migration of whole communities from North East of Asia. Main haplogroup also defines the dominant genetic makeup not just origin.
You wouldn't find any SEA nation having dominant 0-Page23 .
Thailand =B, F, and M7 haplogroup.
Vietnam =F1
Cambodia= B5Indonesia= B5a in West F1a4 in East.
Laos =O2a1-M95
These all have North Eastern gene but the dominant haplogroups are nor A,O,
You can also find root of communities from the language,
Tibeto burman/Sino tibetan speaking people has a northeastern origin.
Austroasiatic speaker= Khashi in NE,and some small tribes in India, and Cambodian,Vietnamese,Thai,Laos,Indonesia,Philippines.
Burma is different because south is Khmer-dominated,but north is more Tibeto burman.
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Another rule of thumb,the northern u are, the more tibeto burman and the southern u go the more austro asiatic it gets,Indian NE region is generally above South China,Northern thailand and high near Northern burma . But of course that depends on geography too,the Manipur is surrounded by almost impenetrable mountains,Nagaland is literally hills same as Mizoram ,hence the only Austro asiatic speaking community i.e., Khashi entered through Bengal via Bengal sea corridor entering Meghalaya and some parts of assam, bangladesh bordering regions.Other than that NE region hardly had interaction with Austro asiatic historically. And the groups of tribes prefer to be among themselves rather than intermix. Khasi remained khashi and Naga as Nagas in most case.