This soil quality scale measures suitability for growing crops rather than pollution. Pollution impacts that negatively, of course, but there are plenty of natural reasons why an area might be bad for agriculture.

The north of Scotland is also red on this map, and it's definitely not because of human pollution. It's sparsely populated and generally one of the most unspoilt areas of the UK. The soil just happens to be pretty bad for crops. That's part of the reason it was sparsely populated in the first place. I expect Finland could be the same.