Prince William’s Earthshot Prize has announced the 15 finalists for its annual award for companies looking to tackle the world’s environmental crisis.

In its third year, the Earthshot Prize has never been more urgent amid a year of unprecedented heat waves and other climate disasters.

Of the 15 finalists, five will receive $1.1 million to scale their solution as well as other support. The shortlisted candidates are active in fields ranging from fashion to battery making to waste management. But all are focused on taking innovative approaches to addressing an aspect of the climate and biodiversity crisis.

“We’ve got to hang on to optimism,” Prince William said. “It is the biggest driver of change. It is the biggest driver of innovation.”

The Earthshot Prize is backed by an international alliance of organizations, including the Bezos Earth Fund, Breakthrough Energy Foundation, Jack Ma Foundation, Paul G. Allen Family Foundation and Marc and Lynne Benioff. Bloomberg LP, the parent company of Bloomberg News and Bloomberg Philanthropies are both members of the alliance; Michael Bloomberg is the majority owner of the former and the founder of the latter.

Among the finalists are Colorfix, a U.K.-based biotech start-up that wants to make our clothes less polluting. Globally, apparel makers emit more greenhouse gases than aviation and shipping combined. Much of that is tied to fabric dyeing.

Colorfix identifies DNA sequences responsible for a particular color on feathers or plants, and translates that genetic code into microbes. The engineered microbes are then placed in a bioreactor to proliferate through fermentation, the same way beer is brewed, producing colorful dye liquor in a matter of days. That allows dyeing houses to get rid of synthetic pigments derived from fossil fuels, while consuming less water and energy to dye fabrics. The company says it already has customers in Bosnia, Italy and Portugal.

Another finalist, Aquacycl, looks to clean up wastewater’s methane problem. The gas is 80 times more potent than carbon dioxide and lowering emissions could provide relatively quick benefits to the climate. Its founder, Orianna Bretschger, studied how microbes can remove pollutants from wastewater and produce electricity while pursuing a Ph.D. at the University of Southern California. Unlike conventional wastewater treatment methods, Aquacycl claims its solution doesn’t release methane.

Beyond lower emissions, finalists for the prize are also focused on other environmental risks. That includes halting deforestation in the Andes mountains in South America, preventing overfishing with traceable catches and cleaning up the microplastics released from tire wear where vehicles’ rubber meets the road.

Previous Earthshot Prize winners have benefited from the funding and exposure.

The 15 finalists were picked from more than 1,100 applicants by a global panel of scientific, academic, and subject-matter experts. The winners will be unveiled on Nov. 7 in Singapore.