In some regions, especially where public transportation options are limited, driving is the favored way of getting around. But vehicles powered by fossil fuels are a huge source of greenhouse gas emissions. If you drive a car, you can reduce air pollution and lighten lighten your carbon footprint by choosing not to drive. Designate a day to be car-free every week or every month. Pick the days and commit yourself to staying local—or using more environmentally friendly ways of getting around.