Nanomaterials (NMs) are gradually becoming pervasive in the modern world, entering every application for improving the quality of life. Multifaceted uses of NMs in curing diseases, biomedical instrumentation, bioimaging, drugs, and gene delivery, display devices, nanosensors, and biomarkers in several fields ranging from agriculture to industries, healthcare, and environment, have been well recognized. Carbon-based nanomaterials (CNMs) constitute a major type of NMs with broad-spectrum applications including their uses in agriculture. These are synthesized in large quantities via synthetic and biological approaches. Biological approaches are gaining appreciation and momentum, owing to the advantages associated with them, major being their environment friendly or ‘Green’ nature. This topical review focuses on the preparation of CNMs using natural resources, i.e., using the Green Nanotechnology. The up-to-date compilation presented here includes most of the popular green technological methods of producing the CNMs and their immediate uses as anticancer agents, in bio-labelling, as biosensors, in bio-remediation, in cell imaging, in fluorescent inks, and fluorescent dyes, as plant growth inducing agents, in nano-probes, in light-emitting devices and other applications. It is intended to update the reader with the state-of-the-art knowledge about the green technological methods for synthesizing CNMs, their uses, current trends, challenges, and future outlook on the topic.

    Abstract
    1 Introduction
    2 Green synthesis of different types of CNMs
        2.1 Green synthesis of carbon nanotubes (CNTs)
        2.2 Green synthesis of the graphene, graphene oxide (GO), and graphene quantum dots (GQDs)
        2.3 Green synthesis of carbon quantum dots (CQDs) and florescent carbon quantum dots (FCQDs)
        2.4 Green synthesis of carbon nanoparticles (CNPs)
        2.5 Green synthesis of carbonaceous nanospheres and graphene nanoribbons
        2.6 Green synthesis of carbon dots (CDs) and fluorescent carbon dots (FCDs)
    3 Concluding remarks
    Acknowledgements 
    References

• Sandeep Kumar Verma(SAGE University, M.Sc. Biotech. NTCC Project, SAGE University)
• Ashok Kumar Da(Department of Industrial Chemistry, College of Applied Sciences, Addis Ababa Science and Technology University)
• Saikat Gantait(Crop Research Unit (Genetics and Plant Breeding))
• Yogita Panwar(M.Sc. Biotech. NTCC Project, SAGE University)
• Vinay Kumar(Department of Biotechnology, Modern College, Savitribai Phule Pune University)
• Marian Brestic(Department of Plant Physiology, Slovak University of Agriculture)