Which is the MAIN cause of China's water and air pollution problems?
A. Overpopulation
B. Global warming
C. Factorys and Industries
D. Lack of government regulation

China consumes almost as much coal annually as all other countries combined, and coal burning in the country is the biggest source of both air pollution and greenhouse gas emissions, the leading cause of climate change. Chinese cities are among the most polluted in the world.
B is your answer

Where are the choices?