Once regarded as one of the most polluted rivers in the world, the Dong River (also called Dongjiang), which flows through Guangdong and provides most of the drinking water in Hong Kong, is now significantly cleaner than it was 10 years ago.

“A water improvement project that was commissioned by Hong Kong and provincial governments in 2003,” is apparently to thank, according to a report by the South China Morning Post last week.

However, one of the interesting side effects of a cleaner Dong River has been an increase in freshwater peach blossom jellyfish. So, if you’re feeling like going for a dip in the nice clean water, perhaps you ought to think again.

Does that mean you’re better off swimming in China’s dirty rivers? No, that would just be madness. Asides from all the toxins and pollutants (and probably sewage) in unclean, smelly rivers, there may well be jellyfish floating around in there too.

Bloomberg reported over the weekend that jellyfish can tolerate warm and polluted rivers:

“If anyone is to blame for recent destructive jellyfish “blooms,” as their regional population explosions are called, it is not them, but us. That’s because jellyfish can tolerate waters that are warm and polluted — conditions that human activity promotes. And as people have fished predators and competitors from their midst, jellyfish reign.”

What does the message seem to be? You’re better of just staying out of China’s rivers altogether.

Photo credit: Bloomberg