When the pollution index is in the weather forecast, it is one.

According to the air quality index: 0 ~ 50 is the best; 5 1 ~ 100 is good, 10 1 ~ 200 is light pollution, 20 1 ~ 300 is moderate pollution, and > 300 is heavy pollution. In the weather forecast, the pollution index is 15 1 ~.

Therefore, choose: d.