Thanks SeventhHeaven for answering ,
My main confusion is if the MEA altitudes on the approach plates are considered restrictions ,or if ATC will ever gives an aircraft the clearance to descend below them .
For instance for Athens LGAV airport ABLON 1B arrival [ index 20-2 ] , is the 7000 ft MEA between ABLON and KEA VOR a restriction that no aircraft can descend below unless instructed by ATC ?