Read the following passage and answer the question.
What is Mahabharata? It is one of the two major Hindu Mythological Sanskrit epics of India. It is the narration of the great eighteen-day Kurukshetra war between the hundred Kauravas and the five Pandavas, the children of two brothers. Interwoven with many stories and a multitude of characters, it comprises philosophical and devotional material. It also contains the Bhagwat Gita, the much revered Hindu religious text. Mahabharat is not meant to be read as a pastime for amusement. You have to delve deeply into it and understand the characters and their actions and reactions. Once involved in the story, you will find yourself playing out so many roles, identifying something similar with the characters as they appear in the story. The Story The story begins with Hastinapur’s King Shantanu of the Kuru dynasty marrying River Goddess Ganga. Bhishma, one of the prominent characters in Mahabharata, was their son. Ganga left them to carry out her godly duties, and Shantanu married Satyavati and had two sons with her. Vichitravirya, one of the sons, became the king after him. He fathered three sons, Dhritarashtra, Pandu, and Vidur. Dhritarashtra being blind, Pandu became the king supported by Bhishma. Dhritarashtra married Gandhari and had a hundred sons, the Kauravas. Pandu married Kunti and Madri, and with the blessings of different gods, the five Pandavas were born. Unknown to everyone, Kunti was already an unwed mother to her oldest son, Karna. Having brought prosperity to his kingdom, Pandu decided to retire to the forest, entrusting the kingdom to the care of Dhritarashtra. After Pandu and Madri’s death, Kunti came back to Hastinapur with the five boys. The cousins, Kauravas, and Pandavas never got along. There were failed attempts by the Kauravas to kill them. And after one such conspiracy, the Pandavas with their mother went into hiding. In this period, Arjun married Draupadi, and they all went back to Hastinapur. But they were exiled to the forest for thirteen years when in a game of dice, Yudhishthir lost everything to the Kauravas. On their return, Duryodhana refused to give back the kingdom, and the stage was set for the greatest battle despite Lord Krishna’s attempts to bring peace. The war went on for eighteen days and ended with the defeat of the Kauravas. Yudhishthir was crowned the King.

Why were the Pandavas exiled? 

Because of Yudhishthir's fate