Here is an explanation from Michael Swan:
We normally use can and could to say that things are possible in general: people are able to do them, the situation makes them possible, or there is nothing to stop them. May and might are not used in this way:
These roses can grow anywhere.
Can gases freeze?
I think I understand the point. My question is: Does the following sentence fall into this category? Does it show "a general possibility"?
Every year, about one billion tourists travel around the world. Tourism is traveling for entertainment, health, sport or learning about the culture of a nation. Tourism can be domestic or international. Domestic tourists travel to different parts of their own country. International tourists travel abroad. (Source: Iran's English Coursebooks)