THE price of petrol is set to increase by 1c per litre on May 3, the Department of Minerals and Energy said on Wednesday. In a statement the department said the price of diesel will remain the same, while illuminating paraffin will increase by 3c per litre. The statement said the increase is attributed to the price of crude oil, which peaked at US32,6 on March 7, and which is still “a dominating factor in local fuel prices”.