Process for dehydration of a mono-alcohol, or of a mixture of at least two mono-alcohols, having at least 2 carbon atoms and at most 7 carbon atoms into olefins having the same number of carbons, the process comprising the following steps: i.) providing a catalyst composition; ii.) providing a feed comprising said mono-alcohol, or said mixture of at least two mono-alcohols, optionally water, optionally an inert component; iii.) contacting said feed with said catalyst at conditions effective to dehydrate at least a portion of said mono-alcohol; iv.) recovering an effluent and removing water, the inert component if any and unconverted alcohols if any to get said olefins having the same number of carbons as said mono-alcohol characterized in that said catalyst composition comprises a modified crystalline aluminosilicate has an acidity between 350 and 500 μmol/g measured by temperature programmed desorption of ammonia, wherein catalyst composition is obtained by a process comprising the following steps: a) providing a crystalline aluminosilicate having a Si/AI framework molar ratio greater than 10 and chosen among ferrierite, FU-9, ISI-6, NU-23, Sr-D, ZSM-35, ZSM-57 or SUZ-4 or any mixture thereof; b) optionally shaping and/or calcining said crystalline aluminosilicate; c) steaming said crystalline aluminosilicate, or said shaped and/or calcined crystalline aluminosilicate: - at a temperature ranging from 100°C to 380°C; and - under a gas phase atmosphere, without liquid, containing from 5 wt % to 100 wt % of steam the rest being one or more gas selected from N 2, CO 2, Ar, He, CH 4, air, or any mixture of thereof; with preference air is selected from air and depleted air containing below 10 wt% of oxygen as based on the total weight of the depleted air, preferably below 5 wt%, more preferably below 1 wt%; and - at a pressure ranging from 2 to 200 bars; and - at a partial pressure of H 2 O from 2 bars to 200 bars; and - said steaming being performed during at least 30 min and up to 144h. i.) providing a catalyst composition; ii.) providing a feed comprising said mono-alcohol, or said mixture of at least two mono-alcohols, optionally water, optionally an inert component; iii.) contacting said feed with said catalyst at conditions effective to dehydrate at least a portion of said mono-alcohol; iv.) recovering an effluent and removing water, the inert component if any and unconverted alcohols if any to get said olefins having the same number of carbons as said mono-alcohol a) providing a crystalline aluminosilicate having a Si/AI framework molar ratio greater than 10 and chosen among ferrierite, FU-9, ISI-6, NU-23, Sr-D, ZSM-35, ZSM-57 or SUZ-4 or any mixture thereof; b) optionally shaping and/or calcining said crystalline aluminosilicate; c) steaming said crystalline aluminosilicate, or said shaped and/or calcined crystalline aluminosilicate: - at a temperature ranging from 100°C to 380°C; and - under a gas phase atmosphere, without liquid, containing from 5 wt % to 100 wt % of steam the rest being one or more gas selected from N 2, CO 2, Ar, He, CH 4, air, or any mixture of thereof; with preference air is selected from air and depleted air containing below 10 wt% of oxygen as based on the total weight of the depleted air, preferably below 5 wt%, more preferably below 1 wt%; and - at a pressure ranging from 2 to 200 bars; and - at a partial pressure of H 2 O from 2 bars to 200 bars; and - said steaming being performed during at least 30 min and up to 144h. - at a temperature ranging from 100°C to 380°C; and - under a gas phase atmosphere, without liquid, containing from 5 wt % to 100 wt % of steam the rest being one or more gas selected from N 2, CO 2, Ar, He, CH 4, air, or any mixture of thereof; with preference air is selected from air and depleted air containing below 10 wt% of oxygen as based on the total weight of the depleted air, preferably below 5 wt%, more preferably below 1 wt%; and - at a pressure ranging from 2 to 200 bars; and - at a partial pressure of H 2 O from 2 bars to 200 bars; and - said steaming being performed during at least 30 min and up to 144h.