HONG KONG—Hong Kong has banned non-residents from entering the city from four African countries and plans to expand that to travelers who have been to Australia, Canada, Israel, and six European countries in the past 21 days due to fears over Omicron. The World Health Organization (WHO) said on Monday the Omicron coronavirus variant carried a very high risk of infection surges, and countries around the world have tightened travel restrictions. In a statement late on Monday, the Hong Kong government said non-residents from Angola, Ethiopia, Nigeria, and Zambia would not be allowed to enter the global financial hub as of Nov. 30. Residents can return if they are vaccinated but will have to quarantine for seven days in a government facility and another two weeks in a hotel at their own expense. “Non-Hong Kong residents from these four places will not be allowed to enter Hong Kong,” the statement …