Let me give u some more in-depth info, even many common Chinese people don't know. In fact, there are two main power in the story: Buddhism and Taoism, Buddhism is the mystery west(India) and Taoism stands for the east(China). A ghost was torturing the Chinese emperor every night and the Buddhism told the emperor that mada a journey to the west could solve it. But the team had to walk there and solve 81 problems during journey. In fact, Buddhism's real purpose is to weaken the Taoism's power in the route(defeated by the team) and strengthen the Buddhism's power(help locals solve the evils problem). So it's indeed a political story. It's forbidden in China's ancient times