Hungary has powered down its sole nuclear power plant for the first time in its four-decade history, after an extreme drought brought the Danube River to record-low levels, rendering the plant unable to draw sufficient water to cool its reactors. Prime Minister Peter Magyar confirmed that the Paks Nuclear Power Plant, located in central Hungary south of Budapest, was shut down on Sunday. The plant normally supplies between 45 and 50 percent of Hungary's electricity, making the closure an immediate national energy emergency.

The Soviet-built, four-reactor facility at Paks relies on pumping large volumes of water from the Danube through its cooling systems before returning it, slightly warmed, to the river. The ongoing heatwave has pushed the Danube to unprecedented lows — the water level at Paks is expected to fall as far as minus 144 centimetres, well below the previous record of minus 98 centimetres set in 2018, and far past the minus 134 centimetres threshold that forces a complete shutdown. Compounding the problem, the river water itself is significantly warmer than usual, reducing its cooling efficiency, while environmental regulations prohibit the discharge of excessively warm water back into the river to protect aquatic ecosystems. Output had already fallen from a normal 2,000 megawatts to just 240 overnight before the full shutdown was ordered.

To manage the shortfall, the Hungarian government has introduced a series of emergency measures. Freight rail services are being suspended during peak hours, civil servants have been ordered to work from home for at least the first three days of the working week, and all lighting in government buildings is being switched off. Authorities have also asked private companies to follow suit. Water managers have been instructed to impose the strictest restrictions wherever necessary, and bans have been placed on irrigating sports fields and filling swimming pools. Hungary is currently importing as much electricity as possible from neighbouring countries, while gas-fired power stations are running at maximum capacity — though a major gas plant near Budapest experienced a significant outage. Slovakia's Prime Minister Robert Fico stated that his country was closely monitoring the situation and was prepared to assist.

The crisis highlights a structural vulnerability common to several Central and Eastern European countries: heavy dependence on a single large power source with limited investment in diversified or flexible energy networks. The Danube, which flows from Germany to the Black Sea, is one of several major European rivers — alongside the Rhine and the Rhône — that have seen dramatically reduced flows due to months of heat and the retreat of Alpine glaciers that normally feed them with meltwater. Scientists at the World Weather Attribution group have pointed to human-caused climate change as the driving force behind the unprecedented temperatures Europe has experienced since May. France has faced similar nuclear cooling constraints along the Rhône and Gironde rivers for years, and reactors in both France and Romania were also scaled back this year for the same reasons — but Hungary's situation is more acute given its near-total reliance on a single plant.