Maybe one of the biggest issues nowadays is the access to clean water around the globe. This is really a problem! In some parts of Brazil people have to walk like 2 r 3 hours to reach a good place to collect water to drink and it goes without mention Africa or India.
However e new device called Solvatten hopes to provide a solution for this.
It promises to purify 10 liters of waters in 3-4 hours in a sunny day. Similar to a standard jerrycan, the Solvatten can hold 10 liters of water, divided into two 5 liter compartments, each with a clear face. When you open the device and place it in the sun, exposing the two chambers to sunlight. This heats the water to 50-60°C, killing any pathogens which are present in a few hours. An indicator signals when the water is safe to drink (it changes from red to green). The whole process takes 3-4 hours in sunny conditions and 5-6 hours if it is cloudy.
Bellow a video about it using Nepal as case study.