Prices for waste paper boxes in China have risen drastically since the second half of 2016, the China Securities Journal reported on Monday.

“In early April of this year, waste paper boxes, commonly known as yellow paperboard, were only 900 yuan (US$135.28) per ton,” a waste collection station operator in Chengdu said.

“The price rose to 1,200 yuan by the end of April, and reached a peak in August and September. Sometimes, prices could rise 200 to 300 yuan in a day.”

Many regard the banning of imported waste as the leading factor in the recent rise in paper prices.

In July of this year, the General Office of the State Council issued the Proposal on Reform Prohibiting the Entry of Foreign Matter. The plan stated that sorted waste paper would be “prohibited from being imported” by the end of the year.

According to customs statistics, in 2016 China imported more than 500 million tons of uncleaned waste paper, which converted into about 450 million tons of waste paper pulp — 13% of total waste paper pulp imports.

In addition, environmental protection is also believed to be affecting the trend in higher paper prices.

“Due to environmental protection, many small paper mills and scrap acquisitions were shut down, which also led to a rise in paper prices,” a waste paper acquisition station said.