LONDON – A viral illness in China that has sickened hundreds of people and prompted Chinese authorities to effectively shut down at least three cities is not yet a global health emergency, the World Health Organization said Thursday. The U.N. health agency issued its evaluation after Chinese authorities moved to lock down three cities indefinitely earlier in the day and canceled major public celebrations and gatherings in Beijing during the Lunar New Year holiday period to try to contain the evolving outbreak. During a news conference in Geneva, WHO Director-General Tedros Adhanom Ghebreyesus said that while the epidemic was clearly a crisis in China, “it has not yet become a global health emergency.