The British are staging a rolling series of limited attacks at Ypres. These are meant to attritional, inflicting more damage on the Germans than the Allies are taking, but casualties are heavy on both sides. Since the recent assault on the Menin Road and the fighting that followed, some 20,000 losses have been suffered by British and Australian forces. German losses are about the same.
Now the British shift focus to attack Polygon Wood (so named for its curious shape on the map). Again the British are helped by relatively dry weather conditions and good preparations. British and Australian troops push into the wood (or what is left of it) and establish themselves on more easily defended positions from which German rear areas can be observed. The Germans launch vigorous counter-attacks but are unable to dislodge the British from their gains. Casualties on both sides are heavy: well above 10,000 men each.
Australian troops advance (Wikipedia)
Australian troops wearing respirators (Wikipedia)