Olfactory offences are smells that are considered unpleasant or offensive. They can be caused by a variety of sources, such as decaying food, sewage, smoke, and chemicals. The term 'olfactory offences' is derived from the Latin word olfacere, which means 'to smell'. The crossword solution for this term is 'ODORS', which refers to any strong, unpleasant smell. ODORS can be caused by a variety of sources, including bacteria, mold, and chemical compounds.