<prompt> A problem village is one where ?Source of water 1.6 km awayWater available 15 meters depthExcess of fluoride in waterAll of the above  <response>: Ans. is d i.e., All of the above A problem village has been defined as one Where no source of safe water is available within a distance of 1.6 km, or Where water is available at a depth of more than 15 meters, or Where water source has excess salinity, iron, fluorides and other toxic elements, or Where water is exposed to the risk of cholera. 