A spike in North Korea’s exports to China last month consisted almost entirely of ferro-silicon, customs data shows, as the potentially illegal export used in silicon production made a surprising return to above and beyond even pre-pandemic levels.

Data from China’s General Administration of Customs (GAC) shows North Korea exported nearly 16 million kilograms of ferro-silicon (HS Code 72022100) worth $11.7 million in Dec. 2021, by far the country’s top export last month.

The DPRK is likely barred from exporting ferro-silicon under U.N. Security Council (UNSC) Resolution 2371. However, Beijing has exploited disagreements over the precise