God had pity on the people of Nineveh because they turned from their evil ways. When Jonah warned the Ninevites about God's coming judgement because of their wickedness, they repented and turned from their evil ways. They fasted, wore sackcloth and ashes, and turned to God in prayer. God saw their repentance and had mercy on them, and He did not bring the destruction that He had warned of. Therefore, God had pity on the people of Nineveh because of their repentance and turning from their evil ways.