China is facing its worst drought in a decade, with water in parts of the Yangtze River at the lowest level in 142 years, state media has reported.
Millions of people were short of water, and dozens of ships had run aground in the river since October, reports said.
Officials said low water levels in the Yangtze were not linked to construction of the massive Three Gorges Dam.
China faces droughts and floods annually but has seen a recent increase in extreme weather conditions.
In the major Yangtze port city of Hankou, water levels fell to 13.98m (46ft) in early January - the lowest level since records began in 1866, China Daily said, citing local media.
"This year's drought is rare," the daily quoted a local farmer as saying.
"Just days ago, I saw ship after ship running aground. I have never seen that before."
Supporters say the dam will prevent flooding and generate electricity
Water levels in other rivers and reservoirs in China are also reported to be at record lows.
Officials said that an earlier than expected dry season was to blame for the drought.
Authorities have already warned that climate change could make weather conditions in China much tougher in the years ahead.
Large amounts of water were also stored behind the Three Gorges Dam last month, causing a 50% reduction in the flow volume of the Yangtze, China Daily said.
But the Yangtze River Water Resource Commission said this was not the cause of the problem, the daily added.
Supporters of the dam say it will prevent devastating floods and provide much-needed hydroelectric power but there are concerns over its environmental impact.