Question

the motto, \dilution is the solution to pollution,\ caused local air quality to improve, but decreased air quality ___.
upwind
downwind
nearby
locally

Explanation:

The phrase "dilution is the solution to pollution" implies that pollutants are spread out. Wind direction is key. Upwind would be against the wind, so pollutants wouldn't accumulate there. Nearby and locally are similar to the improved local air quality mentioned. Downwind is the direction the wind is blowing to, so pollutants would be carried there, decreasing air quality.

Answer:

B. downwind