More than half of the U.S. population lives amid potentially dangerous air pollution, with national efforts to improve air quality at risk of being reversed, a new report has warned.

A total of 166 million Americans live in areas that have unhealthy levels of either ozone or particle pollution, according to the American Lung Association, raising their risk of lung cancer, asthma attacks, heart disease, reproductive problems and other ailments.

During the 872-day German siege of Leningrad in World War II, in which an estimated 1.1 million civilians died, a small band of workers devoted themselves to safeguarding a priceless trove of 200,000 seeds at the Institute of Plant Industry. Then the world’s largest seed bank, the collection had been amassed, in large part, by famed Soviet botanist Nikolai Vavilov during expeditions to 64 countries. 

More than 170 governments declared an end to the fossil fuel era on Friday, using the signing ceremony for the landmark Paris agreement as an occasion to renew their vows to fight climate change.

Surfing is synonymous with riding waves all day, jamming to Jack Johnson, chilling around a beach bonfire by night and sleeping in a VW van before doing it all over again.

But there’s another idea that should also come to mind when imagining the idealized life of a surfer dude or dudette: science.

SunEdison Inc SUNE.N, once the fastest-growing U.S. renewable energy company, filed for Chapter 11 bankruptcy protection on Thursday after a short-lived but aggressive binge of debt-fueled acquisitions proved unsustainable.

In its bankruptcy filing, the company said it had assets of $20.7 billion and liabilities of $16.1 billion as of Sept. 30.

Senegal's President Macky Sall sees a link between climate change and security, in particular when it comes to the jihadist threat in the Sahel.

"Global warming exacerbates receding water levels... and when water becomes scarce there are fewer agricultural lands and conflict begins," Sall told AFP in an interview after signing the Paris climate deal at the United Nations.

Palestinian President Mahmud Abbas told world leaders at a U.N. ceremony Friday that Israel must stop "destroying" the climate in the Palestinian territories.

"The Israeli occupation is destroying the climate in Palestine and the Israeli settlements are destroying nature in Palestine," Abbas told the gathering of 175 countries signing a landmark climate deal.

Japanese automaker Mitsubishi Motors plans to compensate customers in a bid to limit the fallout from a fuel-efficiency cheating scandal, the Nikkei reported on Saturday.

Authorities raided the company's office on Thursday after the company admitted it had falsified efficiency data for hundreds of thousands of vehicles.

Around 630,000 Audi, Mercedes, Opel, Porsche and Volkswagen cars are to be recalled in Europe owing to irregularities in their emission of pollutants, a German government source told AFP on Friday.

The German makers have decided to recall the vehicles as a voluntary measure following an investigation launched in the wake of the Volkswagen engine-rigging scandal.

World leaders gather at the United Nations on Friday to sign the Paris climate deal and get the ball rolling on a quick entry into force to start beating back global warming.

French President Francois Hollande and Canada's Justin Trudeau will join US Secretary of State John Kerry for the ceremony attended by more than 165 governments, the largest ever one-day signing of an international agreement.