Why are earthen pots wrapped with a wet cloth during summer?

During summer water is stored in earthen pots to keep it cool. The earthen pot has a large number of minute pores on its surface through which water seeps through continuously and gets evaporated. If we wrap the earthen pot with a wet cloth, then the cloth will help the water to get evaporated faster from its surface. During evaporation, water will absorb the required latent heat from the surface of the wet cloth and will help in faster cooling.