They are formed when a gas such as methane gets trapped in well-defined cages of water molecules forming crystalline solids. It is a solid ice-like form of water that contains gas molecules in its molecular cavities. Natural gas hydrates occur on continental margins and shelves worldwide from Polar Regions to the tropics. Gas hydrate reservoirs are generally associated with biologically rich cold seep ecosystems at the seafloor. Cold seeps are locations where hydro-carbon rich fluid seeps up from below the sea floor, often as methane or hydrogen sulfide.

Source: ForumIAS