Smoke shrouds the Sydney Harbour Bridge in Australia's most populous city on Thursday. Photo: Cassie Trotter/Getty Images

Smoke from Australia's deadly wildfires blanketed the state capitals of Sydney and Adelaide as air quality exceeded "hazardous" levels on Thursday, the BBC reports.

Why it matters: Thousands of people have fled the fires. Per News.com.au, much of the country is on high fire alert, as blazes rage across all six of Australia's states. Six people have died in the bushfires in the eastern states of Queensland and New South Wales.

Residents defend a property from a bushfire at Hillsville near Taree, north of Sydney. Photo: Peter Parks/AFP via Getty Images
A NSW Rural Fire Service firefighter mops up after a bushfire in the suburb of Llandilo in Sydney. Photo: Sam Mooy/Getty Images
Trees are burned black after a bushfire in Old Bar, north of Sydney. Photo: Peter Parks/AFP via Getty Images
Firefighters tackle a wildfire that's threatening a home in Taree, north of Sydney. Photo: Peter Parks/AFP via Getty Images
Fire burns near the small town of Deepwater, near Glen Innes in northern New South Wales. Photo: Brook Mitchell/Getty Images
A dehydrated and injured Koala receives treatment at the Port Macquarie Koala Hospital in Port Macquarie, Nov. 2. Photo: Saeed Khan/AFP via Getty Images
Wildfires burn in the distance as children play on a beach in Forster, north of Sydney, Nov. 9. Photo: Peter Parks/AFP via Getty Images
Australian Prime Minister Scott Morrison comforts 85-year-old Owen Whalan at an evacuation center in Taree, Nov. 10. Photo: Peter Parks/AFP via Getty Images
An aerial photo of the fires over northeastern New South Wales, Nov. 9. Photo: Tom Bannigan/AFP via Getty Images
The remains of a house destroyed by fire in Old Bar, north of Sydney, Nov. 10. Photo: Peter Parks/AFP via Getty Images
A fire rages in Bobin, north of Sydney, Nov. 9. Photo: Peter Parks/AFP via Getty Images

Editor's note: This article has been updated with new details throughout.

Go deeper

10 mins ago - World

Nuclear free-for-all: The arms control era may be ending

Illustration: Aïda Amer/Axios

The mushroom clouds over Hiroshima and Nagasaki have remained unreplicated for 75 years in part because the U.S. and Soviet Union — after peering over the ledge into nuclear armageddon — began to negotiate.

Why it matters: The arms control era that began after the Cuban Missile Crisis may now be coming to a close. The next phase could be a nuclear free-for-all.

Pelosi, Schumer demand postmaster general reverse USPS cuts ahead of election

Schumer and Pelosi. Photo: Alex Wong/Getty Images

House Speaker Nancy Pelosi (D-Calif.) and Senate Minority Leader Chuck Schumer sent a letter to Postmaster General Louis DeJoy on Thursday calling for the recent Trump appointee to reverse operational changes to the U.S. Postal Service that "threaten the timely delivery of mail" ahead of the 2020 election.

Why it matters: U.S. mail and election infrastructure are facing a test like no other this November, with a record-breaking number of mail-in ballots expected as Americans attempt to vote in the midst of a pandemic.

2 hours ago - Science

CRISPR co-discoverer on the gene editor's pandemic push

Photo illustration: Aïda Amer/Axios. Photos: Brian Ach/Getty Images for Wired and BSIP/UIG via Getty Images

The coronavirus pandemic is accelerating the development of CRISPR-based tests for detecting disease — and highlighting how gene-editing tools might one day fight pandemics, one of its discoverers, Jennifer Doudna, tells Axios.

Why it matters: Testing shortages and backlogs underscore a need for improved mass testing for COVID-19. Diagnostic tests based on CRISPR — which Doudna and colleagues identified in 2012, ushering in the "CRISPR revolution" in genome editing — are being developed for dengue, Zika and other diseases, but a global pandemic is a proving ground for these tools that hold promise for speed and lower costs.