Credit... Andrew Testa for The New York Times As Britain found itself even more isolated on Tuesday because of a new variant of the coronavirus spreading there, the European Commission advised European Union members to lift blanket bans on travelers, recommending testing or quarantines instead. The commission, the bloc’s executive arm, said on Tuesday that member states should move swiftly to reverse travel bans imposed over the past few days in an effort to stop the spread of new variant of the coronavirus that has emerged in Britain. Credit... Jae C. Hong/Associated Press LOS ANGELES — As California’s new coronavirus cases, hospitalizations and deaths continue to soar, the nation’s most populous state has emerged as the epicenter of the pandemic heading into a dangerous holiday week. 