Task: Question Generation
Input (English): Background Paragraph: One result of air pollution is acid rain. Acid rain is precipitation with a low (acidic) pH. This rain can be very destructive to wildlife. When acid rain falls in forests, freshwater habitats, or soils, it can kill insects and aquatic life. It causes this damage because of its very low pH. Sulfur oxides and nitrogen oxides in the air both cause acid rain to form ( Figure below ). Sulfur oxides are chemicals that are released from coal-fired power plants. Nitrogen oxides are released from motor vehicle exhaust. 
Story: The ecologist moved from Aspen, where there was no air pollution, to Seattle which experienced a lot of air pollution. He started studying the weather there as well.
Output (English): Which city had rain with a higher pH?