Blue carbon refers to the carbon captured and stored by coastal and marine ecosystems, particularly through the growth of vegetated areas like mangroves, salt marshes, and seagrasses. These ecosystems play a crucial role in mitigating climate change by sequestering significant amounts of CO2 from the atmosphere, thus contributing to carbon cycling and promoting overall environmental health. Understanding blue carbon is vital for sustainable development and climate action strategies, which are key components of UPSC Prelims GS Paper I, as they address the interplay between environmental conservation and economic growth.