"The European Space Agency estimates that there have been more than 660 explosions, collisions, or anomalous events resulting in fragmentation. As it stands, there are currently more than 1.5 million space debris objects in Earth orbit.

It’s not clear what may have caused the Yaogan-50 (02) satellite to break apart, but it may have been a propulsion or battery failure, or it may have itself collided with another object or space debris."