To convert a Hindu into a Muslim was an easy affair in those days. If a Muslim simply sprinkled water on the body of a Hindu, it was supposed that the Hindu had already become a Muslim. During the transition of the British in Bangladesh during the last Hindu-Muslim riots, many Hindus were converted into Muslims by having cows’ flesh forcibly pushed into their mouths. Hindu society was so rigid at the time of Lord Caitanya that if a Hindu were converted into a Muslim, there was no chance of his being reformed. In this way the Muslim population in India increased. None of the Muslims came from outside; social customs somehow or other forced Hindus to become Muslims, with no chance of returning to Hindu society. Emperor Aurangzeb also inaugurated a tax that Hindus had to pay because of their being Hindus. Thus all the poor Hindus of the lower class voluntarily became Muslims to avoid the tax. In this way the Muslim population in India increased. Chand Kazi threatened to convert the people into Muslims by the simple process of sprinkling water on their bodies.
Ref >> Srila Prabhupada Vani.