NOVELTY - Process (P1) for selective oxidation of hydrogen sulfide in hydrogen sulfide-containing hydrocarbon and/or hydrogen feed gas to elemental sulfur in a reaction zone containing Claus catalyst, involves: (A) reacting in the reaction zone (1) the hydrogen sulfide in the hydrogen sulfide-containing hydrocarbon and/or hydrogen feed gas (3) with sulfur dioxide (4) at a pressure of 4-200 bar (absolute) and 120-160 degrees C, such that the elemental sulfur formed is essentially in liquid form; and (B) contacting the catalyst with a reducing atmosphere at elevated temperatures.    USE - For selective oxidation of hydrogen sulfide in hydrogen sulfide-containing hydrocarbon and/or hydrogen feed gas to elemental sulfur in reaction zone having Claus catalyst (claimed). The gaseous streams include e.g. light hydrocarbons, such as methane, ethane, propane, and gases derived from such light hydrocarbons; natural gas; gases derived from tar sand and shale oils; gases associated with crude oil production; coal, methane or biomass derived synthesis gas; gases such as hydrogen or mixtures of hydrogen (e.g. H2, and CO and/or CO2).    ADVANTAGE - The process provides direct selective oxidation of hydrogen sulfide in gaseous hydrocarbon or hydrogen-comprising streams to sulfur with Claus catalyst, for prolonged times without observing significant loss of hydrogen sulfide conversion. By contacting the catalyst with a reducing atmosphere, the SO42- anions deposited on active sites of catalyst are reduced and sulfated T1O2 compounds, such as TiO(SO4), are effectively converted to back to TiO2. As a result, lifespan of the catalyst is significantly increased. Also no additional sulfur dioxide is formed during the conversion of the hydrogen sulfide. As sulfur formed is in a liquid form, the catalyst remains accessible to reactants and clogging of catalyst or catalyst pores is prevented. There is no need to separate hydrogen sulfide from other gas components, such as in conventional Claus processes. The process is very suitable for removal of hydrogen sulfide from gaseous streams having relatively high content of hydrogen sulfide i.e. up to 80 volume%. The heat released during exothermic oxidation of sulfur can be used to produce electricity. The hydrogen sulfide containing gas can be processed at pressure at which it is produced or at which it becomes available. Thus natural gas can be processed at pressure at which it is produced at well and effluents from hydroprocessing or gasification unit can be processed without depressurizing them.    DESCRIPTION OF DRAWING(S) - The figure shows scheme for performing process for selective oxidation of hydrogen sulfide in hydrogen sulfide-containing hydrocarbon and/or hydrogen feed gas to elemental sulfur in reaction zone containing Claus catalyst.    Reaction zone (1)    Catalytic zones (2a, 2b, 2c)    Hydrogen sulfide-containing hydrocarbon and/or hydrogen-containing feed gas (3)    Stream of sulfur dioxide-containing gas (4)    Effluent of each catalytic zone (6a, 6b, 6c)    Gas/liquid separator (7)    Sulfur combustor (15)    Sulfur dioxide concentration unit (21)