Porous polysaccharides are employed in a wide range of applications and have recently attracted a lot of attention due to their porosity, availability, and exceptional properties like sustainability and biocompatibility. Because of their unique capacity to form porous structures, studies on the use of polysaccharides such as cellulose, chitosan, alginate, and starch as aerogels have recently increased. Polysaccharide-based aerogels are promising for water remediation due to their high porosity, large surface area, and biodegradability; they are eco-friendly and can be functionalized to remove various pollutants. They can effectively adsorb toxic heavy metals such as copper, mercury, and lead and are used to remove coloring dyes from industrial wastewater. Modified polysaccharide aerogels, such as those with hydrophobic properties, are efficient for oil-water separation. This chapter presents recent advancements in polysaccharide-based porous aerogels, including their synthesis and applications in water and soil remediation. The comparison of the supercritical CO2 and freeze-drying processes indicates which drying method is best for understanding the aerogel formation of porous polysaccharides. The drying step in the aerogel synthesis process is particularly important. The limitations and potential for future commercialization of porous aerogels are also discussed, along with the recent uses of polysaccharide aerogels in soil and water remediation.