Abstract: The process and the equipment for reducing emissions of pollutants in flue gases from furnace installations (1, 6) comprises a first furnace installation (1) operated with an air excess of, for example, 15%, and a second furnace installation (6) in which afterburning within the stoichiometric range is carried out, with consumption of the residual oxygen. The flue gases leaving the second furnace installation (6) no longer contain any free oxygen, but contain unburned hydrocarbons, carbon monoxide, nitrogen oxides, sulphur dioxide and sulphur trioxide as pollutants. The first-mentioned pollutants--unburned hydrocarbons, carbon monoxide and nitrogen oxides--are converted on a multi-functional catalyst into carbon dioxide, water vapor and nitrogen. The sulphur of the flue gas is oxidized by means of an oxidation catalyst (12) to sulphur trioxide which reacts with the water vapor contained in the flue gas to give sulphuric acid.