Photo taken on February 19, 2023 shows students participating in an activity to protect the Yangtze finless porpoise in Nanjing, Jiangsu Province. They visited an exhibition hall devoted to the Yangtze finless porpoise, which is under top-level state protection and an important indicator of the Yangtze River ecology, and picked up litter along the river. (CFP Photo)

Photo taken on February 19, 2023 shows students participating in an activity to protect the Yangtze finless porpoise in Nanjing, Jiangsu Province. They visited an exhibition hall devoted to the Yangtze finless porpoise, which is under top-level state protection and an important indicator of the Yangtze River ecology, and picked up litter along the river. (CFP Photo)

Photo taken on February 19, 2023 shows students participating in an activity to protect the Yangtze finless porpoise in Nanjing, Jiangsu Province. They visited an exhibition hall devoted to the Yangtze finless porpoise, which is under top-level state protection and an important indicator of the Yangtze River ecology, and picked up litter along the river. (CFP Photo)

Photo taken on February 19, 2023 shows students participating in an activity to protect the Yangtze finless porpoise in Nanjing, Jiangsu Province. They visited an exhibition hall devoted to the Yangtze finless porpoise, which is under top-level state protection and an important indicator of the Yangtze River ecology, and picked up litter along the river. (CFP Photo)

Photo taken on February 19, 2023 shows students participating in an activity to protect the Yangtze finless porpoise in Nanjing, Jiangsu Province. They visited an exhibition hall devoted to the Yangtze finless porpoise, which is under top-level state protection and an important indicator of the Yangtze River ecology, and picked up litter along the river. (CFP Photo)

A Yangtze finless porpoise was spotted in the Yangtze River in Nanjing, Jiansu Province at around 2:00 pm on February 19. (CFP Photo)