How did the British treat the Indians when they took over India?
British control of India really encompassed two main phases. The first was the period from 1785-1858, when India was under the control of the East India Company (EIC). The EIC was a corporation chartered by the Crown that had virtual sovereignty over India. It had slowly gained control over Indian commerce and territory throughout the eighteenth century, and became especially prominent after the Seven Years' War. The EIC was characterized by corruption and mismanagement, which led Parliament, over time, to establish more and more control over Indian affairs. EIC rule was also deeply resented by many of the Indian people. The EIC sought to exploit social and political divisions of the subcontinent and violently suppressed uprisings using mercenary forces and men conscripted from the local population. Dissatisfaction with EIC rule culminated with a massive rebellion that began in the ranks of these colonial forces, and after it was violently put down in 1858, Parliament placed the subcontinent directly under government rule. This government control was known as the "Raj," and it would last until after World War II. Throughout the Raj, British rulers viewed the Indian people as racially and culturally inferior. They also alienated ordinary Indian people even as they made alliances with Indian elites, who ruled in agreements with the Crown. Again, the British created divisions by choosing Indians to serve in the colonial bureaucracy, nurturing a subclass of elites that were resented by the masses. They legally and socially discriminated against Indians and people of mixed race, who were also shunned by Indian people. They forced Indian farmers into a global market and mandated the growth of commercial crops, which left them open to the ups and downs of supply and demand. Overall, the wealth generated by India under the Raj was not invested back into India (though the British did construct considerable infrastructure, roads in particular). In sum, the British treated Indians as subject peoples, useful only inasmuch as they could enrich the British empire.
For the most part, the British did not treat the Indians very well when they took over India.
There can be many different reasons to explain the poor treatment of Indians at the hands of the British during the take over of India. One reason would be economic. Britain saw India as an investment opportunity. British control over India guaranteed new revenue streams. They were able to take cloth, spices, and others items from India and sell them for profit. English exports from India were produced in large quantities to guarantee economic growth. The desire for wealth helped to drive the British control of India. In the process, many British people treated Indians as a means to an end.
I think that another reason why Indians were mistreated was because of a culture clash. The British came to regard much of Indian culture as "backwards" or "superstitious" or "uncivilized." Such views enabled the British to denigrate Indian culture and label those who adhered to such beliefs and practices as inferior. The British failed to understand the nuanced cultural reality that defined so much of India. They did not account for the level of divergent social, cultural, and religious reality that defined so much of the subcontinent. Many British viewed their purpose as "improving" the condition of India This process resulted in the relegation of Indians to the margins of many aspects of life. Such beliefs led to a social order that placed the British at the highest of positions and kept Indians subservient. Exclusionary practices, force, and political manipulation were means used to silence Indians while maintaining this hierarchy. This became another way in which Indians were mistreated at the hands of the British.