The differences between the Hindus and the Muslims were undoubtedly be accentuated by the policy of "divide and rule" systematically pursued by the British throughout the 19th century. As far back as 1821 a British officer wrote in the Asiatic journal ; "Divide et Impera should be the motto of our administration," and the policy was supported by high British officers. At first the policy was to favour the Hindus at the expense of the Muslims, for, as Lord Ellenborough put it, " that race is fundamentally hostile to us and therefore our true policy to conciliate the Hindus." It was not till the seventies when the Hindus had developed advanced political ideas and a sense of nationalism that the British scented danger then they began to favour the Muslims against the Hindus.
Ofcourse ther were basic differences between the two communities till the Aligarh movement or the british policy only accelerated the contradictions between the two communities. Sometimes their tensions developed into serious clashes between the two communities. Early in the nineteenth century there was such a violent outbreak at Varanasi. In Oct. 1809, the Hindu mob of the city stormed the great mosque of Aurangazeb. Though well authenticated details were lacking, it was reported that about fifty mosques were destroyed, the city was given up to pillage and slaughter, and a large number of Muslims were put to death. In 1851, serious riot took place in Bombay.In 1857, the Muslims of Broach attacked the quarters of the Parsis and killed some of them. In 1871-72, Hindu-Muslim riots with heavy casualities occured in Bareilly and other localities in UP. In 1874, Bombay witnessed another riot when Dadabhai Naoroji and Feroz shah Mehta were eye witnesses. In 1877, a series of riots took place which continued till the end of 19th century.The Calcutta riots in 1897 had a different origin. That occurred due to some court verdict in favour of Sir Jatindra Mohan Tagore against the claim of a mosque by the Mohammedans.