One of the deadliest epidemics in decades has dented energy demand and industrial output in China, cutting carbon dioxide emissions by about 100 million metric tons—close to what Chile emits in a year. A new analysis by the climate nonprofit Carbon Brief found that the widespread impact of the virus—including travel restrictions, longer holidays, and lower economic activity—means that neither has recovered from the usual lull around the Chinese New Year, a roughly two-week festival that began this year on January 25.