Shale gas is a natural gas that is found trapped within shale formations, which are sedimentary rocks made of clay and other minerals. This type of gas is extracted through a process called hydraulic fracturing, or fracking, where water, sand, and chemicals are injected into the ground to create fractures in the rock, allowing the gas to flow more freely. The discovery and extraction of shale gas have significantly increased natural gas production in countries like the United States. This has led to lower energy prices and a shift towards cleaner energy sources, as natural gas emits less carbon dioxide compared to coal when burned for electricity.