China is reportedly strictly abiding by UN sanctions banning shipment of industrial equipment to North Korea. 

A source with knowledge of North Korean affairs said Chinese authorities are not granting customs clearance for steel and metal construction equipment that the North ordered from Chinese companies. 

According to the source, China is even barring simple construction tools such as spades and pickaxes from being carried into the North. 

UN Security Council Resolution 2397, adopted last December, bans North Korea from importing heavy machinery, industrial equipment and transportation vehicles.