Fracking is a technique used to release gas and oil from shale rock.
- It involves drilling down before fracturing layers of rock using a pressurised liquid.
- Water, sand and chemicals injected into the rock then allow gas to be released.
- The process enables petroleum, natural gas and other substances to be extracted.
More top news
Dan Biggar says the Wales team are enjoying their World Cup journey and will continue to do so after the pool stages.
A cold night ahead with clear spells and mist patches forming by the early hours!
The story of how Wales have taken their qualifying campaign by storm, to put themselves within touching distance of Euro 2016.