At that time Cholera was considered to be an air-borne disease and the authorities were sceptic that it was being spread by drinking (contaminated) water. However they yielded to his strong plea for removal of handle from suspected pump. This reportedly resulted in containment of the disease and prevented further deaths.
Image from Flickr is by McManly
View location in Google Earth / Google Street View ad Maps
Main source of info and more info: Wikipedia / John Snow Website by UCLA
Credits: Flb via Google Earth Community