These have been classified according to their permanent acquired traits.

As per permanent traits, about 85% tribal population lives in parts of Gujarat, Rajasthan, West Bengal, Orissa, Madhya Pradesh, Jharkhand, Chhattisgarh, Maharashtra and Andhra Pradesh. 11% lives in the North Eastern states and 4% in the rest of India.

Share of tribals in state population is the highest in the North-Eastern States. It is 30% in Assam, over 60% combinedly in Arunachal Pradesh, Meghalaya, Mizoram and Nagaland. In other words, their concentration is upto 95% of total tribal population in these North Eastern states.

In terms of language, these are castegrised into—Indo-Aryan, Dravidian, Austric and Tibeto-Burman. 1% tribes speak Indo-Aryan while 3% Dravidian language, Austric language is almost known to tribals and 80% speak Tibeto-Burman.

In physical-racial terms, tribals are classified in Negrito, Australoid, Mongoloid, Dravidian and Aryan categories. In terms of size, tribals range between seven million to less than hundred person (i.e. in Andaman Nicobar Islands). Biggest tribes are the Gonds, Bhils, Santhals, Oraons, Minas, Bodos and Mundas each at least a million people. As per census of 2001, their share in total population of India is 85 million person million person or about 8.2%.

As per Acquired traits : Classification is based on : (i) Mode of livelihood and (ii) Extent of absorption into Hindu society through Sanskritisation. They are fishermen, food gatherers, hunters, shifting cultivators, peasants and plantation and industrial workers on the basis of livelihood. On the basis of assimilation into Hindu Society, tribals are incorporated in Hindu society according to their attitudes and status mainly financial. It rests on the desire of tribal people.

Role of ideas of separation in caste system:

(i) It has engendered discrimination, inequality and prejudices among people.

(ii) As per Varna system, some people are declared Brahmins, Kshtriya and vaisya i.e. the upper caste while a majority of others as Shudra. There is also a section of society excluded from these four Varnas and people of these classes have been declared as depressed or untouchables.

(iii) This idea of separation and hierarchy has brought drastic changes in social processes since the Post Vedic Era to colonial and Post-Colonial Period.

(iv) This ideology imposes caste by birth and compels people to compare his/her skills only to hereditary occupations viz. a barbers son will or can do only hair cutting and a cobbler's son will do shoe manufacturing occupation.

(v) This ideology had divided society and this was the sole reason for India's falling in the trap of slavery for more tham two centuries in the past.

(vi) As per caste system every person has a distinct caste and every caste has a specified place in the hierarchy of all castes.

(vii) Castes also involve sub-divisions within themselves, i.e. these have sub-castes and sometimes, sub-castes may also have sub-sub-castes. It is called a segmental organisation.

(viii) Ideas of separation and hierarchy proved beneficial for some castes while others are condemned to a life of endless labour and subordination.

(ix) Each caste is supposed to be different form and therefore, separated from every other caste.

(x) Different and seperated castes do not have an individual existence and they can only exist in relation to a larger whole, the totality of society consisting of all castes.

(xi) Economic or military/physical power is closely associated with social status so that those in tend to be of high status. People defeated in wars were assigned to low caste status.

(xii) Each caste has its own place in the system which cannot be taken by any other caste. It allows no mobility.

(i) Urban upper castes have benefited the most from the developmental policies implemented by government of India after independence. Now they had suffice wealth and educational resources hence, they need not support from caste based claims. They werein glut of affluence.

(ii) Upper caste elite were able to benefit from subsidised public education/professional education in science, technology, medicine and management. Their people till then were ascended to higher positions in government services and had made a debut in legislature.

(iii) The third generations from these groups had acquired economic and educational capital sufficient to ensure the best opportunities in their life.

Rules imposed by the caste system

(i) Caste is determined by birth hence, nobody is allowed to change his caste, leave it or choose not to join it. An individual found violating caste rules shall be punished from social exclusion.

(ii) One cannot solemnise his marriage with the person (he or she) not member of his own group. It's endogamy recognised under caste system.

(iii) Person of a particular caste shall have strictly observed the rules of food and food sharing.

(iv) A person born into a caste can only practice the occupation associated with that caste.

(v) Shudres and untouchables shall serve the upper castes i.e. Brahmin, Ksatriya and Vaisya popularly called Dvija. They cannot share food with upper caste individuals.

Changes in the caste system doing colonialisation

(i) The British government conducted decennial census from 1881 onwards in which caste based data were collected separately.

(ii) The census conducted under the direction of Herbert Risley in 1901 CE sought to collect information on the social hierarchy of caste i.e. position of each caste in the rank or order.

(iii) Representatives of different castes addressed hundreds of petitions to the Census commissioner in order to enlist them on a higher position on hierarchy of caste system. Prior to that people were reluctant to their castes.

(iv) Upper castes were given preference in the land revenue settlements and related arrangements under British Government.

(v) The Government of India Act. 1935 was passed to give legal recognition to the schedules (list) of castes and tribes marked out for special treatment by the state. From here, the terms scheduled castes and scheduled tribe came into being and subsequently, given place in Constitution of independent India.