Matki, (or Matka) is the Hindustani word for an earthen pot. It is used all over India, as well as Pakistan, Bangladesh and Sri Lanka, as a home "water storage cooler". It has been in use since ancient times and can be found in houses of every class.
Cooling process
The cooling process works through evaporative cooling. Capillary action causes water to seep and evaporate from the mini-pores in the pot, taking the heat from the water inside, thus making the water inside cooler than the outside temperature. Hence it is used only during .