The 8.5-ton airplane is expected to enter Earth's atmosphere between March 24 and April 19. However, the ESA stressed, this is just a rough estimate.
"This aircraft can re-enter Earth in the region of about 43 degrees north latitude and 43 degrees south latitude," wrote Space Debris Office, ESA, based in Darmstadt, Germany last week.
"These areas beyond this latitude need not be taken into account, the ESA is unlikely to provide accurate time and place estimates."
Current predictions call Tiangong-1 will fall around Greece, France, Spain and Portugal.
Map of the area that may be the entry point of Tiangong-1. Tiangong-1 is China's first space-building laboratory. It was launched in late September 2011.
The purpose of China to build this laboratory is to help them understand the technology needed to operate a space station that has a crew.
China plans to send a space station into Earth orbit by 2020.