A stream of mysterious foam has been bubbling out of sewer grates and causing traffic chaos on the streets in a Chinese city.
The foam billowed out from the underground sewers and stretched over 200 metres long across a junction.
Videos emerged on social media showing cleaners flushing it with water but the foam continues to rise.
The white foam covers most of the road, leaving dozens of cars stuck in traffic.
According local media Kan Kan News, the foamy substances appeared on Tuesday afternoon in the city of Xi'an, central China.
Local residents reported the foam to the department of environment and complained of a 'strong, pungent smell'.
Some of them said the foam spewed up to 50 metres high in the air.
Officials took samples of the foam and tested it as non-acidic, suggesting that it could be caused by a mass flow of washing up liquid leak.
They added that the substances would not cause harm to the public.
They sent seven road washing trucks to the scene and spent one hour to wash it back down the sewer.
It's said the traffic has resumed with no disruptions.
