Oil sands are most commonly found in Venezuela’s Orinoco Basin and Alberta, Canada. Modern technology has made the extraction of crude bitumen, or unconventional oil, from these oil sands much easier. The crude oil that is extracted from traditional oil wells is a free-flowing mixture of hydrocarbons, whereas oil sands yield a highly viscous form of petroleum. Increasing world demand for oil and higher petrol prices have made the economic viability of extracting oil sands approach that of conventional oil. Oil sands have been described as one of the dirtiest sources of fuel. Compared to conventional oil, four times the amount of greenhouse gases are generated from the extraction of bitumen from oil sands. Additionally there is an impact on the local environment. Tailing ponds of toxic waste are created whenever the tar sands are washed with water. Proponents of oil sands development point to the land that has already been reclaimed following oil sands development. Also, that there will be considerably less surface impact once technology innovations have allowed oil sand reserves to be drilled rather than mined.