OSTRAVA, Czech Republic -- In this part of northeastern Czech Republic, huge piles of coal are stacked up ready to sell to eager buyers and smoke belches from coal-fired plants that are ramping up instead of winding down. Ostrava has been working for decades to end its legacy as the most polluted area of the country, transitioning from an industrial working-class stronghold to a modern city with tourist sights. But Russia's war in Ukraine has triggered an energy crisis in Europe that as paved the way for coal's comeback, endangering climate goals and threatening health from increased pollution.