Is the Three Gorges Migration a Political Factor or an Economic Factor? Our teacher said it was politics! ! Why?

Politics and economy are complementary, which can be considered as matter and consciousness, economy as matter and politics as consciousness. Canyon immigration is an administrative act of government departments, which seems to be dominated by political factors. However, according to the principle that material feelings and consciousness react to material, the economic base determines the superstructure, so economic factors play a greater role.