Firefighters in the Australian state of New South Wales are battling what is being called the worst fire ever seen in the region. Eight separate bushfires have ＿＿（51）＿＿ north of Sydney to create what people are calling a "mega-fire." The gigantic ＿＿（52）＿＿ is just an hour's drive from Sydney. Tens of thousands of homes, businesses and other properties are in its path. The giant inferno is burning across a ＿＿（53）＿＿ of land covering over 300,000 hectares. The front of the mega-fire is roughly 60km wide. Authorities say it is burning out of control and is too vast to ＿＿（54）＿＿ . Fire Service Deputy Commissioner Rob Rogers said: "We cannot stop these fires. They will just keep burning until conditions ease." People in Sydney are suffering from hazardous and toxic smoke from the fire. The city is ＿＿（55）＿＿ in the choking smoke. Residents have received advisories about exercising outside.