Romania has shut down its only nuclear power plant, Cernavodă, because the Danube River’s water level is too low. On Thursday, the second of the plant’s two reactors was turned off after water levels fell below the safe point for cooling. This plant normally supplies about 20% of Romania’s electricity, making it very important for the country.

The shutdown happened because a severe drought has made the Danube River much smaller. There has been record heat in Southeast Europe for weeks, causing emergency actions to fail. The cooling systems could not get enough water, so the government decided to stop the plant’s operations for safety.

As a result, the Romanian government is now importing more electricity and increasing production from coal, wind, and hydropower. Officials say homes will have electricity, but some big factories like Dacia and Ford have been asked to pause work to help protect the power supply.