Pope Francis rode in a carbon-free popemobile at his Mass in Nagasaki, an appropriate choice in line with his environmental concerns.
Organisers say Francis used a Toyota hydrogen-powered Mirai, customised with a stand and handrails. He will use a similar model while in Tokyo.
The pope held a big Mass at a Nagasaki city baseball stadium. Earlier Sunday, he demanded world leaders renounce atomic weapons and the Cold War-era doctrine of deterrence, and paid respects at a memorial for the 26 martyrs.
Environmental protection is one of Francis' key agenda items and is also part of the theme of his Japan visit.