The article discusses the potential of hydrogen fuel cell buses as an alternative to diesel buses. The researchers found that while fuel cell buses are more expensive, they could be a good option in the future due to the ban on diesel vehicles. Using hydrogen from renewable sources in fuel cell buses could greatly reduce CO2 emissions. However, the main barrier is the high initial cost of fuel cell buses, which could decrease with more buses being produced. Overall, a stronger transport policy is needed to consider the environmental impact of different types of buses.