Dr Nema is involved in research, teaching, and consulting in the field of Environmental Engineering and management. He has published 80+ research papers in referred international Journals. He has guided 21 PhDs and 58 master's theses. His main research focuses on the analysis of environmental systems, environmental impact and risk assessment, and integrated waste management, etc. He also works in the area of application of heuristics in decision making related to environmental management issues in multi-criteria, multi-objective, multi-decision makers' paradigm.

Dr Nema has contributed as expert member in Central Pollution Control Board�s steering committee for Environmental Action Plan for Critically polluted Areas, and technical committee for utilization of hazardous waste as a supplementary resource or for energy recovery or after processing under Rule 11 of Hazardous Waste (Management, Handling and Transboundary Movement) Rules 2008; Expert Member for CPHEEO, MoUD, Govt of India Committee for Preparing Manual on Sewerage and Sewage Management; Expert Member for MoEFs Project Steering Committee and Technical Expert Committee for Remediation of Hazardous Waste Contaminated Dump Sites; and Expert Member for the State Environmental Appraisal Committee for evaluating Proposals. Dr Nema had been Vice-Chairman GATE from 2012 to 2014, Chairman GATE in 2015, Vice-Chairman JEE (Advanced) in 2016, Chairman JEE (Advanced) in 2017, Associate Dean (Hostel Management) from 2018 to 2020, Dean (Student Affairs) from 2020 to 2022, Head, Department of Civil Engineering from 2022 to 2024. He is presently working as a Professor at Indian Institute of Technology, Delhi and Deputy Executive Director at IIT Delhi � Abu Dhabi campus.