KATHMANDU, April 19 -- Four years ago, on a Saturday just before noon, the earth below us began to move. The sense of helplessness overwhelmed us as we tried to hold on to something not moving, and quickly realised that everything was moving. Telephone poles swayed, buildings bobbed, ponds overflowed, birds took to the air as trees shook.

The Dharara Tower crumbled, killing at least 60, and 700 temples and monuments came down in clouds of dust. Over 1,400 health facilities, 700,000 homes, 32,000 classrooms were damaged, and nearly 9000 people lost their lives across Central Nepal.

A month later, the Post Disaster Need Assessment (PDNA) put the cost of the damage at over $8 billion. The earth kept moving in hundreds of aftershocks, some of...