Each day, 26 million students in the United States ride a bus to and from school. Most of these buses are powered by diesel engines. They release greenhouse gases that trap heat in Earth’s atmosphere, contributing to climate change. That’s why, this past spring, President Joe Biden announced the Clean School Bus program. It will provide $5 billion to schools to replace old diesel buses with cleaner models. These include buses that run on electricity or fuels like hydrogen and natural gas, which produce fewer harmful emissions.