This smart pre-air conditioner invention helps Japanese fight the unbearable heat in the cities, such as Tokyo. At specific times when the heat is the highest, everyone is organized to come out with a bucket of water and pour it on the pavement. The trick is to make as many people as possible do it simultaneously around the city, since only in that way this may work. The phenomenon is similar to that applied in refrigerators: the liquids trap heat as they turn into gas.
Mission Uchimizu happens all around Japan, not only in Tokyo. Generally, around 70% of Japanese people are aware of the campaign. According to traditions uchimizu is done whilst wearing yukata robe and using a bamboo bowl. Uchimizu is part of daily summer routine—they are sprinkling water at the entrance of their homes, outside shops or other businesses. It is viewed as a courteous act of respect towards neighbours and Japanese traditions.