This photo taken on March 21, 2023 shows a view of the blooming ottelia acuminata in Dianchi Lake in Kunming, southwest China's Yunnan Province. Ottelia acuminata, as an indicator species of the environment, exists in fresh water. (Xinhua/Chen Xinbo)

This photo taken on March 21, 2023 shows a view of the blooming ottelia acuminata in Dianchi Lake in Kunming, southwest China's Yunnan Province. Ottelia acuminata, as an indicator species of the environment, exists in fresh water. (Xinhua/Chen Xinbo)

This photo taken on March 21, 2023 shows a view of the blooming ottelia acuminata in Dianchi Lake in Kunming, southwest China's Yunnan Province. Ottelia acuminata, as an indicator species of the environment, exists in fresh water. (Xinhua/Chen Xinbo)

This photo taken on March 21, 2023 shows a view of the blooming ottelia acuminata in Dianchi Lake in Kunming, southwest China's Yunnan Province. Ottelia acuminata, as an indicator species of the environment, exists in fresh water. (Xinhua/Chen Xinbo)

This photo taken on March 21, 2023 shows a view of the blooming ottelia acuminata in Dianchi Lake in Kunming, southwest China's Yunnan Province. Ottelia acuminata, as an indicator species of the environment, exists in fresh water. (Xinhua/Chen Xinbo)

This photo taken on March 21, 2023 shows a view of the blooming ottelia acuminata in Dianchi Lake in Kunming, southwest China's Yunnan Province. Ottelia acuminata, as an indicator species of the environment, exists in fresh water. (Xinhua/Chen Xinbo)