India has enough reserves of limestone to enable thermal power plants to install flue gas desulphurization (FGD) systems by 2022 in order to meet the new emission norms for the sector. Although the study on flue gas desulphurization systems refutes thermal power industry’s contention that the country does not have enough limestone which has raised concerns about availability of limestone and use of its by-product, FGD gypsum. Limestone is a key raw material in most FGD systems for controlling sulphur dioxide (SO2) emissions and a large number of coal-based thermal power plants have to install FGD systems. They would require only 7 to 10 million tonnes of limestone annually for operating FGD systems. This is less than 3 per cent of India’s present limestone consumption. For use in FGD, high-quality limestone with minimal impurities is desirable. Industry experts believe that producing additional high-quality limestone would not be a challenge given our large reserves. Moreover, regional distribution of limestone reserves shows that access will not be a problem as a majority of power plants are located within 200 km of a limestone mine.