The article delves into the exploration of naturally occurring hydrogen reserves in the Earth's geological subsurface as a potential clean energy source for hard-to-abate industries. It discusses the conditions necessary for the development of natural hydrogen resources, including the processes of hydrogen generation, migration, accumulation, and preservation. The review examines two key mechanisms for natural hydrogen generation within the continental crust: water-rock reactions and radiolysis of water via radioactive elements. It highlights the potential of various terrane types for hydrogen accumulations and emphasizes the low-carbon footprint of exploiting natural hydrogen. However, the article also cautions that natural hydrogen reserves do not provide a regenerating system on short timescales and should not be considered a renewable resource. Key points from the article include the vast energy potential of natural hydrogen reserves, the essential factors for the accumulation and economic recovery of hydrogen gas, the presence of high-purity hydrogen accumulations, and the significance of helium as an analogue to hydrogen in geological exploration. The research underscores the importance of understanding geological controls on hydrogen generation pathways and the limitations of mantle-derived hydrogen gas in near-surface applications. Transitioning to net-zero emissions necessitates a shift from fossil fuel use, with hydrogen playing a crucial role in various industries. While low-carbon hydrogen production technologies are available, their high costs have hindered widespread deployment. The article compares different hydrogen production methods, such as 'green hydrogen' from water electrolysis and 'black' or 'grey' hydrogen from fossil fuels, highlighting the cost differentials and carbon footprints. Despite challenges, the article envisions a future where natural hydrogen could become a highly competitive and sustainable source of hydrogen, aligning with the global goal of achieving net-zero emissions by 2050.