Running on gas: South Africa's greener bus fleet

At the United Nations 21st Conference of the Parties - better known as COP 21 - representatives from over 190 countries will thrash out a global treaty to address climate change.

It is an issue which often receives less attention than it should in the developing world, but there are pockets of action. In South Africa, the city of Johannesburg is on a drive to reduce carbon emissions by rolling out a fleet of buses that run on compressed natural gas.

The BBC's Taurai Maduna has been finding out how it works for Africa Business Report.