Green nanoparticleNanoparticle synthesisSynthesis has various benefits over conventional chemical and physicalPhysical approachesApproach. Green synthesisGreen synthesis uses natural resources like plant extractsPlant extract, microorganismsMicroorganisms, or biopolymers, which makes it an economical and ecologically beneficial alternative to standard methodsMethods that sometimes entail dangerous chemicals, significant energyEnergy usage, and complicated procedures. This technology is typically less hazardous, produces less waste, and emits fewer dangerous byproducts, resulting in a cleaner and safer manufacturing process. Furthermore, green synthesisGreen synthesis is consistent with sustainabilitySustainability ideals, making it a desirable methodMethods for generating environmentally friendly nanomaterialsNanomaterial. However, problems exist that prevent widespread implementation of green synthesisGreen synthesis. Concerns include ultimate product uniformity, lengthy reaction timesReaction time, and raw material availability. In contrast to chemical approachesApproach, green synthesisGreen synthesis frequently relies on natural processes, which can be slower and less effective, resulting in longer production durations. Furthermore, particle sizeSize differences can have an impact on the qualityQuality and repeatability of green-synthesised NanoparticlesNanoparticle. Their broad usage may also be hampered by the lack of easily available or scalable raw materials, such as certain plant extractsPlant extract or microbialMicrobial strains, for large-scale synthesisSynthesis. This paper extensively covers the techniquesTechnique for green nanomaterial synthesisNanomaterial synthesis, critically evaluating the related limits. The primary goal is to identify important hurdles and constraints impeding the creation of environmentally benign metallic NanoparticlesNanoparticle, as well as to offer new pathways for further study. These include identifying novel natural sources, optimizing synthesisSynthesis conditions, and increasing scalability. The insights offered may lead to substantial breakthroughs in green synthesisGreen synthesis, encouraging new and sustainable solutions in nanotechnologyNanotechnology.