Kathmandu, March 16 -- On March 11, a three-wheeler pickup drove into Neemkhotiya village in Bardiya. On the back of the truck, there were five bio-sand filters meant to be delivered and distributed to families in the village. The van stopped near the village's community hall, and the driver and his helper unloaded the filters. They then drove back to the filter factory in the nearby town of Gulariya to get the next batch. The truck would make several trips to deliver all 40 filters.

As soon as the filters were unloaded near the village's community hall, a group of children quickly gathered around, like bees around flowers. Many of them laughed in excitement at seeing the filters, which were painted bright blue. Over the next two days, m...