Ten years ago, upper stages were left in space without any special precaution at the end of their mission. Due to propellant residuals on board, some of these stages (including an Ariane 1 third stage) exploded and produced an important amount of debris, sometimes in regions where the Space Debris Density was already critical. The problem has been solved for Ariane European launchers: general rules, aiming at launcher debris mitigation, are applied to Ariane 4 and 5 launchers design and operation. These cover from multiple launch capability to passivation of Ariane 4 and 5 upper stages. This policy, promoted by CNES in an international effort to establish rules on this subject, will likewise be continued for the Ariane 5 derivatives now under study.