Why Ukraine is struggling to hold on to the ruined city of Pokrovsk

Russian and Ukrainian troops are locked in a desperate fight in the ruins of Pokrovsk, a road and railway hub at the heart of the Donets River coal basin. The near-emptied city has been the target of a grinding Russian offensive for more than a year – and one that has exposed the struggle Kyiv faces in manning a front line stretching some 1,250 kilometres.