Dirt Floors Can Kill You. This Graduate Might Have a Solution.

For the full experience, including photographs of EarthEnable floors, please visit the National Geographic website.

Days after graduating from business school at Stanford University in 2014, Gayatri Datar set off for Rwanda to pursue an unorthodox goal: to rid the world of dirt floors, which can make people sick.

"There are bugs all over the place. Termites. Jiggers. Worms," she explains. "Babies don't have diapers, so kids poop and pee on the floors. They're hard to clean. They don't look good. People hate them." Yet more than one billion people live on dirt because they can't afford anything better.

Datar's start-up nonprofit, EarthEnable, sells an earthen floor made of locally sourced clay, pebbles, and sand, sealed with a proprietary eco-friendly varnish. It costs about $70 per home, far less than concrete.

EarthEnable struggled at first. Getting raw materials to rural villages proved costly. Masons had to be trained to install the floors. Quality was spotty. Datar, 34, says: "Everything that could go wrong did go wrong."

These days EarthEnable is faring better. More than 4,400 earthen floors have been installed, Datar reports, and customers love them. EarthEnable has raised money from foundations, the U.S. Agency for International Development, and a Dutch competition that supports green entrepreneurs. Best of all, Datar is working closely with Rwandan government officials who say they too want to eliminate dirt floors.