Chinese architect Kongjian Yu, globally recognized as the “father” of the sponge city concept, was killed in a plane crash in Brazil along with the other three passengers, the local police announced today.

The 62-year-old Kongjian Yu was a leading figure in sustainable urban development. The “sponge city” concept revolves around replacing urban surfaces with porous materials and green areas to better absorb water into the soil and mitigate flood risks.

According to the Athens-Macedonian News Agency (ANA-MPA), the other three victims were Brazilian filmmakers Luís Fernando Feres da Cunha Feres and Rubens Crispim Junior, both documentary directors and producers, and the pilot and owner of the aircraft.

The cause of the accident, which occurred Tuesday night in a rural area of the Pantanal—a vast wetland in the southern Amazon, in the state of Mato Grosso do Sul (central-western Brazil)—has not yet been determined, according to the police.

Kongjian Yu arrived in Brazil in early September to participate in the São Paulo Contemporary Art Biennial and was traveling to the Pantanal to film a documentary with the two filmmakers. “His concept of ‘sponge cities’ has been applied in more than 1,000 projects in 250 cities,” added the CAU (Council of Architects), emphasizing that the architect “advocated nature-based solutions to address urban flooding and the impacts of the climate crisis.”

Yu participated in the São Paulo International Architecture Biennial program last week. According to the newspaper Estadão, the Chinese professor subsequently joined a trip with filmmakers who were making a documentary about his work.

Yu gained global recognition as an architect and urban planner when the Chinese government adopted his sponge city concept, using nature-based solutions to absorb and retain water instead of relying on concrete infrastructure that diverts it. His idea has since been implemented in hundreds of locations across China, as well as in urban areas in countries ranging from the U.S. to Russia.

Turenscape, the architecture and design firm based in Beijing that Yu founded in 1998, specializes in landscape architecture, urban design, and ecological restoration. Yu led Turenscape from its founding as the firm’s chief designer, developing it into a team of more than 500 specialists, according to the company’s website.