White foam oozes on to Xi'an road. Photo: Beijing News

Residents in Xi'an, Northwest China's Shaanxi Province are calling on environmental authorities to find out how a stinky, white foam emerged from a sewer and covered 200 meters of a local road.

The environmental protection bureau in Xi'an suspected the foam was some kind of chemical detergent that leaked from an as-yet unknown source, the Beijing News reported on Tuesday.

An online video shows the foam deep enough to cover half of a car's wheel, making driving more than a little precarious. "It's snowing, snowing!" a passerby said in a video. Residents said they found the smelly foam leaked from sewer grates.

The road was cleaned up in 45 minutes.

Beijing News