Kong Hainan (R) watches as a chef cooks a dish with ottelia acuminata at the dining hall of Shanghai Jiao Tong University in east China's Shanghai, May 29, 2025.

Kong Hainan is the chair professor and doctoral supervisor with Shanghai Jiao Tong University and head of a major science and technology project of water pollution control and management on Erhai Lake in southwest China's Yunnan Province. He had led a team to work in Yunnan for nearly 20 years to improve the water quality of Erhai Lake.

Ottelia acuminata, known as an indicator of water quality, once bloomed in Erhai Lake. Since the 1990s, due to the deterioration of the water quality of the lake, the plant became hard to be found. Thanks to the efforts of Kong's team and local authorities, the water quality of Erhai Lake has gradually improved, and ottelia acuminata flourished again.

In 2020, Kong retired at the age of 70. He took out his personal savings to initiate a fund to train personnel for the protection of Erhai Lake and to support scientific research on its conservation. In recent years, the artificial cultivation area of ottelia acuminata in Yunnan has reached 3,000 mu (200 hectares), and the plant has become an important vegetable for local people. Shanghai Jiao Tong University also successfully developed the storage and preservation technology of ottelia acuminata, and extended its shelf life to 14 days. The vegetable has now become a popular dish on dining tables in cities outside Yunnan. (Xinhua/Liu Ying)

Ottelia acuminata flowers bloom on a project site in Shanghai Jiao Tong University in east China's Shanghai, April 7, 2021. (Xinhua/Liu Ying)

A researcher (L) introduces preservation technology and processing of ottelia acuminata to Kong Hainan at the School of Agriculture and Biology of Shanghai Jiao Tong University in east China's Shanghai, May 29, 2025. (Xinhua/Liu Ying)

This file photo shows Kong Hainan (C, front) and his students on their way to take water samples of Erhai Lake in southwest China's Yunnan Province in November of 2013. (Shanghai Jiao Tong University/Handout via Xinhua)

Kong Hainan is pictured in a lab at the School of Environmental Science and Engineering of Shanghai Jiao Tong University in east China's Shanghai, April 9, 2021. (Xinhua/Liu Ying)

A researcher invites Kong Hainan (L) to try newly developed snacks made from ottelia acuminata at the School of Agriculture and Biology of Shanghai Jiao Tong University in east China's Shanghai, May 29, 2025. (Xinhua/Liu Ying)

Kong Hainan speaks during a lecture on ecological civilization at Shanghai Jiao Tong University in east China's Shanghai, May 27, 2025. (Shanghai Jiao Tong University/Handout via Xinhua)

Kong Hainan introduces a miniature version of the water quality purification system at Erhai Lake on a project site in Shanghai Jiao Tong University in east China's Shanghai, April 7, 2021. (Xinhua/Liu Ying)

Freshly preserved ottelia acuminata is pictured at the School of Agriculture and Biology of Shanghai Jiao Tong University in east China's Shanghai, May 29, 2025. (Xinhua/Liu Ying)

Kong Hainan (front) shares the story of ecology restoration of Erhai Lake and development of ottelia acuminata industry to freshmen at School of Environmental Science and Engineering of Shanghai Jiao Tong University in east China's Shanghai, March 14, 2025. (Xinhua/Liu Ying)

This undated file photo shows Kong Hainan (2nd L) and his team members on a boat in Erhai Lake in southwest China's Yunnan Province. (Shanghai Jiao Tong University/Handout via Xinhua)