Political turbulence in many regions of the world has increased the number of displaced people fleeing complex emergencies and disasters. They often end up in large camps where environmental health measures are insufficientRefugees are people who have crossed an international frontier and are at risk or have been victims of persecution in their country of origin. Internally displaced persons (IDPs), on the other hand, have not crossed an international frontier, but have, for whatever reason, also fled their homes.