I expect those sensors be (extreme?) expensive. Although maybe some poisons can be detected easily, it is very hard to be sure that no others are in, and that would give people the illusion the water is save.
Yes I think so...The sensors are pretty costly but maybe one set of sensors per village can be enough and just what we need if I'm able to devise a system wherein all the various water sources spread accross the village can be tested as one single point, with various sources being closed and open to test at one time and to know which one source has what all characterics!!
Well anytype of purity level is good for them because these people already have 62 mentally impaired kids back in 150 homes in a single village and the elders are in addition to this so ,whatever good we do adds to the total solution, but yeah! we need to be like try to solve as much as we can.
about the cost, if the system does some good pollutants gauging and distillation stuff then we can tap the local government to get the systems financed, After all they are also in the radar of this shit because the stuff which whole of the world and India eats is grown there.