Crafted by a potter named M Sivasamy, this clay pot was designed to help keep produce cool for days.
He made a cylindrical pot made out of clay with a tap on one side and an outlet to pour water on the other side. A smaller pot fits inside the bigger one where you can place your vegetables which is then covered with a lid. The technology is simple — the water in the pot remains cool keeping the vegetables fresh and cool. - BetterIndia
For places with no or limited electricity, this could help immensely. Especially considering terracotta(earthenware) clay is almost used worldwide.
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I think this type of cooling is known in the western world as well for long time. Usually in the form of unglazed terracotta jugs for cooling drinking water. It just turned out refrigerators are way better and faster at it, so the good ol' jug went into the museum.