Rome is making the move to methane buses. Between January and July next year, the Rome city bus company Atac will introduce a fleet of 200 buses using methane instead of petrol. The vehicles will emit 30 per cent less of the polluting chemical carbon dioxide reducing the amount of pollution caused by vehicle emissions by 60 tons a year.

The methane buses are quieter and less expensive: a methane bus will cost 20 to travel 100 km, against the 44 necessary for a petrol-run bus to travel the same distance.