"I have an interesting theory about where the zombies came from in World War Z. In the opening credits of the movie, you see everything crowded with people and overpopulated. Later, you see that all the wildlife started dying. What if the zombies actually came from pollution as a way to punish humanity for destroying the earth? I know the virus came from China, but it's important to consider the fact that it’s the most polluted country in the world."
