Many places in the world need more fresh water. Every country is trying to find ways to turn salt water into fresh. Why aren't there many factories like the Symi factory? In some places the sun is not hot enough. Or it does not shine every day. In such places other ways of heating sea water can be used. These ways cost more money, but they work faster than the sun. By boiling sea water with high heat a lot of fresh water can be made quickly. But heating is not the only way to get fresh water from salt water. Other ways are tried. One way is freezing. The fresh part of salt water freezes first. To get fresh water, the bits of ice are taken out. Which way is the best? The one that gives the most water for the least money. It may be a different way for each place. Symi's way seems very good for small, hot places. It does not make much water at a time. But the factory is easy to build and costs little. That is why people in many dry places talk about Symi. What fact doesn't the passage mention  ?
New ways of getting fresh water. A lot of fresh water can be made quickly by heating. The best way is to get the freshest water with the least money. The Symi's way doesn't work in dry places.