What are the most challenges faced the procurement departments all over the world?

Delivery of items by the supplier at the promised period, and delay in transferring the payment by the accounts department to the supplier, the procurement team is unable to receive the required items on time.

From my experience, I believe, it is the delivery of items by the supplier at the promised period. Sometimes, it don't happen and affects the project and the buyer has to suffer the heat in the meetings. Another factor that I have seen is , due to the delay in transferring the payment by the accounts department to the supplier, the procurement team is unable to receive the required items on time.

Currency Fluctuation, Enviornment control & Country Relations, these 3 factors are the most challenging for procurement department all over the world.

Lack Vendors information and payments to existing one

selection right vendors , insuring delivery time with alternative as plan B or C  for material and equipment , right communication with engineering team , controlling cost with saving .

geting materials required for the project in cheapest price so that finally we are lesser than the budget price