blockage = state of being blocked

• A blockage in a coronary artery
• The pumps are prone to blockage
• There is a blockage in the drain pipe.

blockade = the enclosing or surrounding of a place to keep goods or people from entering or leaving

• The authorities blockaded roads in and out of the capital.
• Striking lorry drivers agreed to lift their blockades of main roads.
• The militant protesters blockaded the whole area around city hall.