But, there is not evidence of "true Asiatic Cholera" prior to 1781, in which the first well-documented epidemic occurred. Having begun in southern India, it would later spread to eastern India and eventually Sri Lanka. Cholera was endemic to the lower Ganges River. At festival times, pilgrims frequently contracted the disease there and carried it back to other parts of India on their returns, where it would spread, then subside. The first cholera pandemic started similarly, as an outbreak that was suspected to have begun in 1817 in the town of Jessore. Some epidemiologists and medical historians have suggested that it spread globally through a Hindu pilgrimage, the Kumbh Mela, on the upper Ganges River. Earlier outbreaks of cholera had occurred near Purnia in Bihar, but scholars think these were independent events. In 1817, cholera began spreading outside the Ganges Delta. By September 1817, the disease had reached Calcutta on the Bay of Bengal and quickly spread to the rest of the subcontinent.  By 1818 the disease broke out in Bombay, on the west coast.