The correct answer is option D
One thing that is the main cause of the air pollution that is common everywhere is that it occurred in the industrialized areas.
The setup of industries has increased the amount of air pollution in the environment as it increases the amount of harmful gases in the environment.
The gases that causes air pollution are carbon dioxide, carbon monoxide, sulfur dioxide, et cetera are released from the industries.
Hence, it is the main and common cause of air pollution.
