[The Conversation Africa] South Africa's latest fuel price increase, which came into effect on 1 December, put the cost of petrol over the R20 per litre mark (about US$1.25) in parts of the country for the first time. The increase sparked public outcry. The Conversation Africa's Nontobeko Mtshali asked energy sector expert Rod Crompton to share his insights into what influences the price - which is adjusted monthly - and to explain how it's calculated.