The city i live in Sofia, just got 20 electric busses [0], and are planning to bring 142 new LPG (propane) busses.
This is a big deal! However, given that about half of the country's electricity is still from coal, not sure how "clean" those busses really are. (30-35% is from Nuclear power)
[0] https://sofia.bg/web/sofia-municipality/start/-/asset_publis...