Following the success of IWHT2011, IWHT2013, IWHT2015, IWHT2017, and IWHT2019, the 6th International Workshop on Heat/Mass Transfer Advances for Energy Conservation and Pollution Control (IWHT2021) will continue to be held in Harbin, China, August 13-16, 2021. The objective of this workshop is to provide an international forum for exchange of latest technological information as well as for dissemination of high-quality research and development on heat/mass transfer problems in the area pertinent to energy conservation and pollution control. The workshop will be of particular value and interest to researchers, scientists, engineers, and practitioners who are working in heat/mass transfer field of energy conservation and pollution reduction.