The word “Thug” is derived from “Sthag” of Sanskrit, which means “sly”. The ancient Indian society was tolerating towards the petty crimes and there were regimes to punish the professional criminals in ancient India. However, by the time of colonial rule, the menace of professional crimes was costing too much to the society.
The thugs were brutally suppressed in British India. In suppression of Thugs, along with Lord William Bentinck, one more name cherished is William Henry Sleeman. Sleeman was initially a soldier and later became the administrator. In 1835, the ‘Thugee and Dacoity Dept’ was created by William Bentinck and William Henry Sleeman was made its superintendent. He was later promoted as its Commissioner in 1839.
The term Criminal Tribes Act (CTA) refers to various pieces of legislation enforced in India during British rule; the first enacted in 1871 as the Criminal Tribes Act, 1871 applied mostly in North India.
This extremely oppressive act notified certain communities as criminal tribes.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 (IPC). First tribe that was notified under this act was Hur of Sindh. Gradually, as many as 198 tribes were brought in its ambit.

The Act was extended to Bengal Presidency and other areas in 1876, and, finally, with the Criminal Tribes Act, 1911, it was extended to Madras Presidency as well. The Act went through several amendments in the next decade and, finally, the Criminal Tribes Act, 1924 incorporated all of them.
The Act was repealed in August 1949 and former “criminal tribes” were denotified in 1952. It was first repealed in Madras Province in 1949, after a long campaign led by Communist leaders such as P. Ramamurthi and P. Jeevanandham, and Forward Bloc leader U. Muthuramalingam Thevar.
when the Act was replaced with the Habitual Offenders Act 1952 of Government of India, and in 1961 state governments started releasing lists of such tribes.