criteria to be adivasi or not are the aspirational movements Demands for tribal classification

Demands for tribal classification
An additional difficulty in deciding whether a group meets the
criteria to be adivasi or not are the aspirational movements created
by the federal and state benefits, including job and educational
reservations, enjoyed by groups listed as scheduled tribes (STs).[61]
In Manipur, Meitei commentators have pointed to the lack of scheduled
tribe status as a key economic disadvantage for Meiteis competing for
jobs against groups that are classified as scheduled tribes.[58] In
Assam, Rajbongshi representatives have demanded scheduled tribe status
as well.[62] In Rajasthan, Haryana and other northern states, the
Gujjar community has demanded ST status, even blockading the national
capital of Delhi to press their demand.[63] In several cases, these
claims to tribalhood are disputed by tribes who are already listed in
the schedule and fear economic losses if more powerful groups are
recognized as scheduled tribes; for instance, the Rajbongshi demand
faces resistance from the Bodo tribe,[62] and the Meena tribe has
vigorously opposed Gujjar aspirations to be recognized as a scheduled
tribe.

 Endogamy, exogamy and ethnogenesis
Part of the challenge is that the endogamous nature of tribes is also
conformed to by the vast majority of Hindu castes. Indeed, many
historians and anthropologists believe that caste endogamy reflects
the once-tribal origins of the various groups who now constitute the
settled Hindu castes.[65] Another defining feature of caste Hindu
society, which is often used to contrast them with Muslim and other
social groupings, is lineage/clan (or gotra) and village exogamy.[66]
[67] However, these in-marriage taboos are also held ubiquitously
among tribal groups, and do not serve as reliable differentiating
markers between caste and tribe.[68][69][70] Again, this could be an
ancient import from tribal society into settled Hindu castes.[71]
Interestingly, tribes such as the Muslim Gujjars of Kashmir and the
Kalash of Pakistan observe these exogamous traditions in common with
caste Hindus and non-Kashmiri adivasis, though their surrounding
Muslim populations do not.[66][72]

Some anthropologists, however, draw a distinction between tribes who
have continued to be tribal and tribes that have been absorbed into
caste society in terms of the breakdown of tribal (and therefore
caste) boundaries, and the proliferation of new mixed caste groups. In
other words, ethnogenesis (the construction of new ethnic identities)
in tribes occurs through a fission process (where groups splinter-off
as new tribes, which preserves endogamy), whereas with settled castes
it usually occurs through intermixture (in violation of strict
endogamy).[73]

Other criteria
Unlike castes, which form part of a complex and interrelated local
economic exchange system, tribes tend to form self-sufficient economic
units. For most tribal people, land-use rights traditionally derive
simply from tribal membership. Tribal society tends to the
egalitarian, with its leadership based on ties of kinship and
personality rather than on hereditary status. Tribes typically consist
of segmentary lineages whose extended families provide the basis for
social organization and control. Tribal religion recognizes no
authority outside the tribe.Have never been in India Caste system[74]

Any of these criteria may not apply in specific instances. Language
does not always give an accurate indicator of tribal or caste status.
Especially in regions of mixed population, many tribal groups have
lost their mother tongues and simply speak local or regional
languages. In parts of Assam - an area historically divided between
warring tribes and villages - increased contact among villagers began
during the colonial period, and has accelerated since independence in
1947. A pidgin Assamese developed while educated tribal members
learned Hindi and, in the late twentieth century, English.

Self-identification and group loyalty do not provide unfailing markers
of tribal identity either. In the case of stratified tribes, the
loyalties of clan, kin, and family may well predominate over those of
tribe. In addition, tribes cannot always be viewed as people living
apart; the degree of isolation of various tribes has varied
tremendously. The Gonds, Santals, and Bhils traditionally have
dominated the regions in which they have lived. Moreover, tribal
society is not always more egalitarian than the rest of the rural
populace; some of the larger tribes, such as the Gonds, are highly
stratified.

The apparently wide fluctuation in estimates of South Asia's tribal
population through the twentieth century gives a sense of how unclear
the distinction between tribal and nontribal can be. India's 1931
census enumerated 22 million tribal people, in 1941 only 10 million
were counted, but by 1961 some 30 million and in 1991 nearly 68
million tribal members were included. The differences among the
figures reflect changing census criteria and the economic incentives
individuals have to maintain or reject classification as a tribal
member.

These gyrations of census data serve to underline the complex
relationship between caste and tribe. Although, in theory, these terms
represent different ways of life and ideal types, in reality they
stand for a continuum of social groups. In areas of substantial
contact between tribes and castes, social and cultural pressures have
often tended to move tribes in the direction of becoming castes over a
period of years. Tribal peoples with ambitions for social advancement
in Indian society at large have tried to gain the classification of
caste for their tribes. On occasion, an entire tribe or part of a
tribe joined a Hindu sect and thus entered the caste system en masse.
If a specific tribe engaged in practices that Hindus deemed polluting,
the tribe's status when it was assimilated into the caste hierarchy
would be affected.