Why ices are clear?

Normally, we use tap water at the room temperature to make ice at homes. This water may consists of dissolved minerals which are invisible to our naked eyes. If we place the water in the freezer, the water starts freezing from outer side to the inner side and hence much of the minerals are trapped inside the inner layer of the water and the water freezes into ice. This makes ice looks like a cloudy appearance. 
            To make clear ice, some specialized ice makers make water to continuously flow over the surface of a cool container. Thus, water begins to freeze from the bottom of the container, layer by layer. Thus, giving the time for minerals and gases to escape from the top, making the ice clear.

Pic 1 - cloudy ice            Pic 2 - clear ice