Its clear, turquoise waters have made it a favourite among paddle-boarders and Russian Instagrammers keen to capture some Caribbean vibes. But this gorgeous Russian water feature is no picture postcard. It’s a toxic dumping ground, with a pH of more than eight.

A picturesque Siberian lake nicknamed the ‘Novosibirsk Maldives’ has been declared unfit for selfie-takers by a Russian power company, Siberian Generating Company (SGK), which uses the lake as an ash dump for its nearby power station.

Writing on the Russian social networking site VKontakte, the company said that: "Our ash dump at Novosibirsk CHP-5 has become a star of social media networks. You CANNOT swim in the ash dump."

The lake, they went on, was not natural, and was dug by people to house refuse from burning coal. The uniquely turquoise shade comes not from light or water quality, but a combination of metal oxides and calcium salts that could cause a reaction on contact with skin.

Further concern stems from the lake’s bottom, which is apparently so muddy that once stuck it could be "almost impossible" to get free without help. Entirely in caps lock, the company asked that "IN YOUR QUEST FOR A SELFIE YOU DON’T FALL DOWN INTO THE ASH DUMP."

Unfortunately, the warnings seem to have served only to raise the lake’s profile, as the lake has since seen a steady stream of Insta-picnickers, photographers and honeymooners.

Many of the Instagrammers seemed to know about the lake’s content, and even made comments about the taste of the water. It is unclear whether or not they were being serious.