An Indian entrepreneur developed a refrigerator made out of clay, an invention that people can use to store and keep cool their food without using energy at all. Mansukhbhai Raghavbhai Prajapati, a Gujarat-based potter, created this natural MittiCool refrigerator in order to offer an alternative to people from the rural areas, since often they are unable to afford a conventional fridge.
The MittiCool fridge uses the natural cooling effect of water evaporation which keeps vegetables fresh for a long period, even for a week. Furthermore, it is possible to store milk for up to 3 days in it. This fridge is equipped with two shelves: one for vegetables and fruits, and one for storing milk.

The best thing about this invention is that it supposedly preserves the original taste of the food, besides being very affordable. Moreover, it does not run on electric power, which makes it work even in cases of power outages.