Concept:Air pollution is caused by harmful substances released into the air.
Explanation:Industrial fumes release gases and smoke into the air, causing air pollution.
Indiscriminate disposal of solid waste can cause air pollution when waste is burned or decays.
Poor disposal of human excreta can release bad odours and gases into the air.
Fishing with chemicals mainly pollutes water and kills aquatic life, not the air.
Therefore, fishing with chemicals does not directly cause air pollution.
Answer:D. Fishing with chemicals.