Authorities ordered a snap, five-day lockdown in Melbourne on Friday to contain a new coronavirus outbreak, casting doubt on the fate of the Australian Open grand slam tennis tournament, which began in the city this week. Under the restrictions, some five million people in Australia's second-biggest city will have to remain at home for five days from midnight except for a limited number of permitted activities. Premier Daniel Andrews of Victoria state, which includes Melbourne, said the lockdown was necessary to halt an outbreak of the "hyper-infectious" UK strain of Covid-19, which leaked from a quarantine hotel at the city airport. dm/arb/jah