DONETSK, Ukraine — Teachers preside over half-empty classrooms. Cars breeze through streets once chronically choked with traffic. Restaurant windows are boarded up.

Officially, a cease-fire has been in effect in the rebel areas of eastern Ukraine since September. But with war once again looming, and artillery blasts regularly shaking the night in the capital, Donetsk, things are far from returning to normal. Another clear sign of that is the obvious depopulation of much of the rebel-held territory.

Though exact estimates vary, roughly 1.5 million people have left the rebel-held territory in eastern Ukraine, out of a prewar population of about 4.5 million. United Nations figures suggest that about half went to Russia and half to other areas of Ukraine.

Today, for every two people who stayed, one has left, but the raw numbers do not capture the true nature of the catastrophe. By and large, it is the young, the educated, parents with children and those with means who have left, while the aged, the desperate and the destitute have remained behind.