While growing up in Lele village in southern Lalitpur, Pratap Thapa watched his parents plant maize on their terrace farm and wait for the rains. He often wondered how much of their drudgery could be reduced if water could be brought up from a nearby river.

Thapa went on to study engineering at Delft University in The Netherlands, where he obsessed about how to solve the problem of irrigation for his family in the mountains of Nepal in a cheap and sustainable way.

With his Dutch classmate, he invented a unique pump that derived its energy from the kinetic energy of the flow of water, and used it to pump water up. Like all breakthroughs, it was the sheer simplicity of the technology that made it so applicable.