The problem of moving in some of these countries is that you will be going to an area where the tribe you are from is not a welcome member of humanity. Remember that the majority of the conflicts in these Third World countries is still tribal-based and people's lives are at risk if they go to far from where they have been for generations.
Now, on to the purification problem. I agree with the ceramics issue, if, and it appears that it is, the supply of the filters is sustainable.
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"Its not a matter of being ready as it is being prepared" -- B. E. J. Taylor