In today's world, “environment” and “biotechnology” are amongst the most talked about topics. The emergence of complex environmental issues and the potential of biotechnology to tackle them have thrown challenges as well as opportunities to scientists and engineers. In recent times applications of environmental biotechnology have primarily aimed to prevent and alleviate environmental degradation through the use of biotechnology with the focus on bioremediation of soil and water. The selection of the bioremediation process, the type and association of the biological cells, and the participating enzymes are crucial for successful bioremediation. Biofilm-mediated remediation processes are robust while mixed microbial cultures offer combined degradative capabilities of individual microbes. Biological wastewater treatment is vital for protecting human health and the environment. Intelligent bioprocess strategies can generate useful biochemicals concurrently with the treatment of industrial and agricultural wastewater. Production processes termed “green manufacturing technologies” promoting optimal utilization of natural resources through biomass recycling, energy recovery, and waste minimization have been developed. Also, bioprocesses applying microbes – so-called extremophiles – from special habitats (extremes of temperature, salinity, pH) are of significance. The current global microbial diversity is astounding and far more than what we expected 20 to 30 years ago. Direct studies of the environment, e.g., microbial diversity and ecology, have been undertaken through modern methodologies accessible for investigating single bacteria at genetic and metabolic levels. Analysis of microbial communities through metagenomics and an organism's functional output through global gene expression are achieving importance. Other noteworthy biotechnological methods for studying the environment are environmental proteomics, flow cytometry, microarray technology including phenotypic microarrays, microfluidics, next-generation sequencing, and use of stable isotope probes. Determining the exact environmental sources of microbial pathogens causing human infection is fundamental towards reducing the incidence of diseases and human suffering. Some of the promising biotechnologies for pathogen detection are biosensors, microarrays, nucleic acid amplification, mobile genome-based methods, and nanobiotechnology. Lesser release of carbon dioxide should lower adverse impacts on the environment. Promotion of biowaste as a renewable energy source and development of microbial oils as “drop in” biofuels are potential technologies in this direction. Furthermore, microbial fuel cells and microbial electrolysis cells are promising future technologies for energy generation from wastewaters. Thus, environmental biotechnology is currently one of the fastest growing and most practically applicable scientific disciplines. Agenda 21 is an inclusive action plan to be implemented at global, national, and local levels by organizations of the United Nations, governments, and major groups (NGOs, business, industry groups, etc.) in every area where the environment has been influenced by human activity. Agenda 21 envisions environmental biotechnology to meet the objectives by offering technologies for detoxification of hazardous wastes. Moreover, global partnerships between biological resource-rich but technologically and financially less-privileged countries and bioresource-deficient but economically and scientifically advanced countries are achievable to cooperatively utilize biological resources, thus, contributing towards sustainable development. Joydeep Mukherjee School of Environmental Studies, Jadavpur University, Kolkata, India Debashish Ghosh Biofuels Division, Indian Institute of Petroleum, Dehra Dun, India