While Hangzhou residents were witnessing mysterious yellow smoke arising from the streets on Wednesday morning, a new apartment building collapsed in the city of Shenzhen.

Fortunately, prior to the collapse, residents heard distressing noises, prompting a complete evacuation. No casualties have been reported.

Firefighters soon arrived on the scene to control the situation. It’s unclear why the building collapsed. Judging from the clips, two of the buildings six stories dropped underground.