Question

how does the water kept in an eathern pot matka become cool during summer?

Answer 1

Cause it has tiny spores on its surface that realises the latent heat of the pot and hence the water will become cool
Hope it will help

Answer 2

due to small holes present in the walls of the earthen pot the water seeps out slowly as it comes on the outer surface on the earthen pot it is evaporates the energy needed for evaporation is taken from the water kept in the earthen pot as a result water kept in earthen pot become cool

hope it helps you