A、The unbearable traffic noise. B、The worsening global warming. C、The ever-growing cost of petrol. D、The rising air pollution in

Almost half the center of Paris will be accessible only by foot or bicycle this Sunday to mark World Car-Free Day. This is in response to rising air pollution that made Paris the most polluted city in the world for a brief time. Mayor Anne Hidalgo promoted the first World Car-Free Day last year. Hidalgo also has supported a “Paris Breathes” day. On the first Sunday of every month, Paris clears traffic from eight lanes of the main road. About 400 miles of streets will be closed to cars. It is expected to bring significant reduction in pollution levels. Last year’s car-free day showed a 40 percent drop in pollution levels in some parts of the city, according to an independent air pollution monitor, reports The Guardian— and sound levels dropped by 50 percent in the city’s center.
3. What will happen on World Car-Free Day in Paris?
4. What motivated the mayor of Paris to promote the first World Car-Free Day in her city?