(Tajikistan/Afghanistan/China) Porosity of Tajik-Afghan Border Making Beijing’s Involvement in Region More Ominous (The Jamestown Foundation)

In most parts of the world, the lines on maps separating countries are true borders. That is, they are controlled by the governments on one or both sides. But in some places, they remain the quasi-open frontiers they were in the past or have reemerged as such because of recent political changes; those borders are highly porous zones, where people and goods can move more or less freely in one or both directions without much regard to the powers that be.