"Some" is used to talk about an unspecified number. For example, if you're in a class of 50 students, and the teacher says, "Some students didn't hand in their homework," the teacher might be talking about 5 students or 10 students or 20 or 30 or 40, etc. "Some" doesn't say anything about whether it's more than half or less than half.
If most pollution problems have been linked to industrialization, you can say "some" and it'd be correct. The only difference is that "most" is a bit more specific, because we know that it's more than half.