Smoke covers Sydney Opera House in Sydney, Australia, on April 27, 2021. Sydney issued a poor air quality alert as a thick cloud of smoke covered the city due to hazard reductions burns. (Xinhua/Bai Xuefei)
Smoke covers Harbour Bridge with Sydney Opera House in the background in Sydney, Australia, on April 27, 2021. Sydney issued a poor air quality alert as a thick cloud of smoke covered the city due to hazard reductions burns. (Xinhua/Bai Xuefei)
Smoke covers Sydney Opera House in Sydney, Australia, on April 27, 2021. Sydney issued a poor air quality alert as a thick cloud of smoke covered the city due to hazard reductions burns. (Xinhua/Bai Xuefei)
A man angles fish as smoke obscures the view of Sydney, Australia, on April 27, 2021. Sydney issued a poor air quality alert as a thick cloud of smoke covered the city due to hazard reductions burns. (Xinhua/Bai Xuefei)
Smoke obscures the view of Sydney, Australia, on April 27, 2021. Sydney issued a poor air quality alert as a thick cloud of smoke covered the city due to hazard reductions burns. (Xinhua/Bai Xuefei)