A Japanese government survey suggests that the amount of plastic waste held at waste disposal operators has been increasing at some cities since China banned imports in 2017.
The Environment Ministry in March surveyed industrial waste disposal companies and local governments across Japan which oversee those firms.
The world's two top exporters of plastic waste, the United States and Japan, are struggling with the problem of its disposal after China stopped accepting the material.
A US recycling industry group says the United States has been the top exporter of plastic waste over the past decade, and 30 to 40 percent of this type of garbage was shipped to China.
Japan's Finance Ministry has admitted that its local bureau asked to pad the waste removal cost in a land deal in an alleged favoritism scandal.
It revealed this at a Lower House committee meeting on Monday in connection with the sale of state-owned land to school operator Moritomo Gakuen at a fraction of market value.