Turning diesel emissions into ink. Fostering coral reef farms. Empowering female environmentalists.

These are some of the achievements of the winners of the United Nations’ 2018 Young Champions of the Earth Awards.

A panel of judges working with the UN selected seven young people from around the world for their extraordinary work out of thousands of contenders for this year’s prize. Each winner receives $15,000 to fund their ventures and guidance and support from relevant experts.

“For all the urgent environmental challenges we face, these Young Champions are a powerful reminder that the solutions to these challenges are within our grasp,” Head of UN Environment Erik Solheim said in a statement. “Each of these winners has a unique story to tell. Taken together the message our Young Champions send to the world is even stronger: Together we can innovate the future we want while preserving the environment we need.”

Take Action: Ensure All Communities Can Withstand Climate Disaster

The seven winners include Shady Rabab, an activist who teaches young people how to play musical instruments made from garbage in Luxor, Egypt. His “Garbage Conservatoire” initiative gets young people to clean up the streets of the city, while learning a useful and fun skill in the process.

“The children who play music with recycled instruments will be empowered to inspire alternative solid-waste habits and practices,” he said in a video describing his project. “The children will be able to express themselves and, most importantly, foster solidarity and community.”

Hugh Weldon is an entrepreneur from Ireland who developed an app called Evocco, which allows users to scan their receipts to determine their eco footprints.

“We’re engineers,” Weldon told the Irish Examiner. “We like to solve problems, and this is the greatest challenge of our time.”

Read More: These 9 Badass Youth Activists Are Changing the World

“Until we create and fulfil consumer demand, changes aren’t going to happen at the speed that we need,” Weldon said, referring to climate change. “That’s why we moved toward behavioral change and to empower people to learn more about the environment and change the way they spend their money.”

Another winner, Heba Al-Farra, is a Palestinian-Kuwaiti entrepreneur and electrical engineer who’s working to train women to pursue careers in the energy and environment industries in the Middle East and North Africa. She’s working to break down barriers to women’s advancement in both fields and providing networks for creative problem solving.

Plastic waste, meanwhile, is the focus of American entrepreneur and biological engineer Miranda Wang, who co-founded BioCellection, a company that seeks to “make plastic waste infinitely recyclable.”

Read More: Fed Up With Plastic, This Man Got Kenya to Ban It

Wang developed two methods of breaking down plastic waste that can then be repurposed into new materials indefinitely. The first involves shredding plastic, and the second involves the application of immense heat, according to CNN.

Both processes are being fine-tuned, but Wang ultimately hopes to significantly increase the current rate of US plastic recycling, which currently stands at 9%.

"We live in a plastic age, and we can't avoid that material ... [But] frankly our world hasn't been moving forward in innovating plastic recycling for the past decades,” Wang told CNN.

Miao Wang is working to harness the expertise and passion of divers around the world. The Chinese diver created a network called “Better Blue” that enlists fellow divers to become marine conservationists. She provides a platform for divers to collaborate, learn from each other, and plan initiatives.

Then there’s Arpit Dhupar, a Indian mechanical engineer who devised a technique to collect 90% of the particulate matter that comes out of diesel generators, and then turn that substance into ink pigment for printers.

Read More: 6 People Making the Planet Green Again by Planting Trees

More than 7 million people die prematurely from air pollution each year, including 1.1 in India. Since diesel emissions are notoriously dirty, Dhupar’s invention can significantly improve air quality in areas with high diesel fuel use.

The final winner of this year’s prize is Gastor Halpern, a conservationist based in the Bahamas who has nurtured endangered reefs back to health with coral farms. Halpern’s team works by identifying weakened reefs, developing new coral in accelerated land-based farms, and then planting the new coral to promote the overall resilience of a reef.

All together, the Young Champions of the Earth represent an emerging generation of activists who are working to save the planet from the ravages of climate change, overdevelopment, and pollution.

Read More: 6 African Youth Activists You Need to Know

“Once again, young people around the world have come up with amazing new ideas to help protect the environment,” Covestro CEO Markus Steilemann, who judged the competition, said in a statement.