Complex sentence: The second stage is the processing is done in sugar refineries, often located in heavy sugar-consuming regions such as North America, Europe, and Japan, to produce refined white sugar that is more than 99 percent pure sucrose.
Split into simpler sentences: The second stage is often executed in heavy sugar-consuming regions such as North America, Europe, and Japan. In the second stage, white sugar is produced that is more than 99 percent pure sucrose.