When adharma continues to exist in the world, what does it mean to say that the Lord’s mission is complete?

Towards the end of the Ramayana, the Mahabharata and the Chaitanya Charitamrita, the devatas or the Lord’s associates inform the Lord that his mission is now complete. But when adharma continues to exist in the world, what does it mean to say that the Lord’s mission is complete?