Russia has halted its supply of natural gas to Finland, the Finnish state-owned energy firm Gasum has said.   After the EU and US sanctioned Russia over the war, Russia said “unfriendly” countries must pay for gas using the Russian currency, a move the EU considers blackmail. Finland imports most of its gas from Russia but gas accounts for less than a tenth of the country’s energy consumption and Finland said it will not pay for its supplies in roubles.  …