TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalyst: The catalyst is a TiO2-comprising catalyst. Preferred Components: The reducing atmosphere comprises hydrogen sulfide, hydrogen, and/or carbon monoxide (preferably hydrogen sulfide).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: In the process (P1) a sequence comprising step (A) and subsequently step (B) is repeated at least once. The temperature of step (A) is 125-150 degrees C. The pressure in step (A) is 10-150 bar (absolute). The temperature in step (B) is greater than or equal to the temperature of step (A) (preferably the temperature of step (B) is higher than the temperature of step (A)). The pressure in step (B) is (1-200, preferably 5-150, especially 10-150) bar (absolute). The catalyst is contacted in step (B) with the reducing atmosphere at (150-300, preferably 160-250) degrees C. The step (B) involves contacting the catalyst with a reducing gas under such conditions that anionic oxides of sulfur are reduced. The sulfur dioxide and hydrogen sulfide are supplied to the reaction zone in a molar ratio of (0.1-10, preferably 0.2-3, especially 0.2-0.49, particularly 0.3-0.49). At least part of the sulfur dioxide comprising gas is obtained by oxidizing elemental sulfur (preferably elemental sulfur obtained from the process (P1)). The reducing atmosphere comprises at least a reducing agent and optionally an oxidizing agent in a molar ratio of oxidizing agent to reducing agent of (0-0.4, preferably 0-0.2, especially 0-0.1) times the stoichiometric ratio of oxidizing agent to reducing agent. Preferred Components: The reducing atmosphere comprises a hydrogen sulfide-containing hydrocarbon gas (preferably the hydrogen sulfide-containing hydrocarbon feed gas), or a hydrogen-comprising gas (preferably synthesis gas). EXAMPLE - The hydrogen sulfide and sulfur dioxide were contacted with TiO2-comprising catalyst in presence of methane, as follows. The experiment was conducted in quartz reactor, which was made in one piece from borosilicate glass. A filter was inserted to prevent loss of catalyst. The reactor was in down-flow configuration, where gas flow was added from top of reactor and effluents were removed from bottom. In order to prevent premature reaction upstream of reactor, input of sulfur dioxide and hydrogen sulfide was separated until within reactor by concentric feed pipes. The gases were then mixed in chamber above filter before passing through reactor section. The reactor had internal diameter of 0.02 m and height of 0.075 m. The whole reactor was placed in oven set to control temperature. The catalyst was TiO2 (P25), provided in form of particles. The catalyst particles had pore volume of 0.3 ml/g. The catalyst particles were combined with inert SiC particles to create a catalyst bed with well defined flow properties. The resulting catalyst bed had a volume of 24 ml of which 3.8 ml (4 g) was catalyst. The hydrogen sulfide was provided in the form of 1.4 vol.% (based on total volume on mixture) hydrogen sulfide in methane mixture. The sulfur dioxide was provided as a 0.69 vol.% (based on the total volume on mixture) sulfur dioxide in methane mixture. The hydrogen sulfide/methane mixture additionally comprised small quantities (below 10 ppm by volume (ppmV)) of COS. The reactor was pressurized using nitrogen flow. At the start to experiment nitrogen flow was replaced by reactants. Hydrogen sulfide and sulfur dioxide were supplied to reactor separately. The total flow rate was set to 9 Nl/hour (gas hourly space velocity (GVSH) = 2400 hour-1). The temperature was controlled to be 130 degrees C in reactor. The temperature of off-gas from reactor was maintained at 110 degrees C until it reached the back pressure regulator in order to prevent water condensation. The sulfur dioxide to hydrogen sulfide ratio was controlled slightly above stoichiometric ratio of 0.5, such that process was operated in presence of excess of 200 ppmV hydrogen sulfide. The results showed that initially, essentially no sulfur dioxide could be detected in off gas from reactor thus implying full conversion in sulfur dioxide. Hydrogen sulfide conversion, after correction for hydrogen sulfide excess, was measured to be above 99.9%. Starting from approximately 300 hours, sulfur dioxide was detected in off-gas from reactor. The sulfur dioxide concentration increased and reached approximately 40 ppmV at 500 hours. Additionally, COS appeared in off-gas already at 200 hours. Following experiment, catalyst was isolated from reactor and washed with toluene to remove any residual elemental sulfur. Using X-ray diffraction (XRD) it could be shown that no structural modification of catalyst had taken place. Further, XRD analysis showed presence of sulfates on surface of catalyst. The identity of sulfur species as sulfates was confirmed by aqueous extraction followed by ion chromatography analysis.