Denotified Tribes (DNTs), also known as Vimukta Jati, are the tribes that were originally listed under the Criminal Tribes Act of 1871, as "Criminal Tribes" and "addicted to the systematic commission of non-bailable offences." Once a tribe became "notified" as criminal, all its members were required to register with the local magistrate, failing which they would be charged with a "crime" under the Indian Penal Code. The Criminal Tribes Act of 1952 repealed the notification, i.e. 'de-notified' the tribal communities. This Act, however, was replaced by a series of Habitual Offenders Acts, that asked police to investigate a "suspect's" "criminal tendencies" and whether their occupation is "conducive to settled way of life." The denotified tribes were reclassified as "habitual offenders" in 1959.
The name "Criminal Tribes" is itself a misnomer as no definition of tribe denotes occupation, but they were identified as tribes "performing" their primary occupation. The first census was in 1871 and at that time there was no consensus nor any definition of what constitutes a "tribe". The terms "tribe" and "caste" were used interchangeably for these communities.
Denotified Tribes Wikipedia
The UN's anti-discrimination body Committee on the Elimination of Racial Discrimination (CERD) asked India to repeal the Habitual Offenders Act (1952) and effectively rehabilitate the denotified and nomadic tribes on 9 March 2007.
In 2008, the National Commission for Denotified, Nomadic and Semi-Nomadic Tribes (NCDNSNT) of Ministry of Social Justice and Empowerment recommended equal reservations, as available to Scheduled Castes and Scheduled Tribes, for around 110 million people belonging to the denotified tribes, nomadic or semi-nomadic tribes in India. Along with the tribes designated as, "Nomadic" or "Semi-Nomadic", the denotified tribes are eligible for reservation.