I wouldn't consider a peaceful anti-war march to be civil unrest, for instance, but a police chief might. Similarly, I wouldn't consider acts of localized non-violent lawbreaking (like environmental activists chaining themselves to a tree) to be civil unrest; but a timber company official probably believes otherwise.
Civil unrest occurs when anger, frustration, or fear turn disruptive on a mass scale. Or when government officials crack down because they anticipate such disruptions. Crackdowns can lead to further frustration, leading to further crackdowns and so on—especially when the crackdowns look unwarranted and tyrannical.
In other words, civil unrest can arise from the anger of people or the folly of government or both together.
Anger over an unpopular policy, a new war, a collapse of the currency, panic over a pandemic, a food shortage, a bank run—anything like that could cause civil unrest, especially in a population that's already on edge and no longer trusts its authority figures.