The answers to this question point out that Hinduism does not have any permanent hell.
But from the following excerpt from Vana Parva of Mahabharata, a permanent hell exists:
The Yaksha asked,--'O bull of the Bharata race, who is he that is condemned to everlasting hell? It behoveth thee to soon answer the question that I ask!' Yudhishthira answered,--'He that summoneth a poor Brahmana promising to make him a gift and then tells him that he hath nothing to give, goeth to everlasting hell. He also must go to everlasting hell, who imputes falsehood to the Vedas, the scriptures, the Brahmanas, the gods, and the ceremonies in honour of the Pitris, He also goeth to everlasting hell who though in possession of wealth, never giveth away nor enjoyeth himself from avarice, saying, he hath none.
Thus, Hinduism also has the concept of permanent hell, doesn't it? What am I not understanding, if not? How can we interpret this properly?