Natural-gas futures are tumbling following fresh forecasts that suggest January won't be quite as cold as traders believed late last month when

The Urengoy-Pomary-Uzhgorod pipeline was built in the Soviet era to carry Siberian gas to European markets. It became the main conduit to Ukraine’s border with Slovakia from Siberia, passing through the town of Sudzha — which is now under the control of Ukrainian military forces — in Russia’s Kursk region.