Material 1: In 2011, PM2.5 appeared on major online media and newspapers, becoming familiar to the general public and becoming a hot issue of social concern. P

Air quality is measured by its Air Quality Index API (an integer). The larger the index, the higher the level, indicating the more serious the pollution and the more obvious the impact on human health. Therefore, the main measure to reduce the air pollution index in urban areas in the Sichuan Basin is to save energy and reduce exhaust gas emissions. Therefore option A is consistent with the meaning of the question.

So choose: A.