These images show a German lake dyed bright green after the authorities added dye to identify leaks in a broken hot water pipe that left nearly 500 homes without heating.

The pipe burst in the district of Brunswik in the city of Kiel in Germany’s northernmost state of Schleswig-Holstein at around 7.30am on 9th January, leaving hundreds of residents shivering in the cold.

According to the news site Tag24, a pipe burst in the city’s heating network, leaving nearly 500 homes in the immediate area without heating. However, many residents in other parts of the city also reported central-heating failures on social media.

Reports said the districts of Schreventeich and Neumuhlen-Dietrichsdorf on the other side of the fjord were also affected.

Meanwhile, bright green-coloured water ran into the Kleine Kiel, a small, shallow inland body of water in the city centre, after the local authorities added dye.

The authorities assured residents that the dye is harmless, adding that they used it in the water system in the area to help identify leaks.

During works, some of the dye then entered the Kleine Kiel, however, it is biodegradable and caused no long-term effects.

A fire department spokesperson also confirmed: “The dye is harmless and biodegradable.”

The authorities said the reason for the burst pipe on Sunday morning is unclear and still under investigation.