explain drain of wealth during british rule in india

During the 19th century, the theory of 'Drain of Wealth' was advocated by Dadabhai Naroji indicating the exploitative nature of British rule. Throughout the colonial rule, the sole motive of British government was to transform India into a mere supplier of cheap raw materials in order to flourish its own industrial base. Moreover, not only raw materials but India's manpower was also used by the British government with the purpose of spreading its colonial base outside India. Also, the administrative expenses that were incurred by the British government to manage the colonial rule in India were borne by Indian Exchequer. All such exploitative policies of British rule resulted in the drain of India's wealth.