The present invention discloses emissions treatment systems for the removal of NOx from exhaust combustion gases comprising, in the following order, from upstream to downstream: a) means for the injection of ammonia or an ammonia precursor solution into the exhaust gas stream, and b) a catalytic device comprising at least one carrier substrate, a material zone A comprising a first V/TiO2 SCR catalytically active composition SCRfirst which comprises at least one oxide of vanadium supported on titanium dioxide, a material zone B comprising a second V/TiO2 SCR catalytically active composition SCRsecond which comprises at least one oxide of vanadium supported on titanium dioxide, wherein the two material zones are affixed to the at least one carrier substrate in such a way that the exhaust gas first comes into contact with material zone A and then with material zone B, and wherein the ratio Vfirst:Vsecond of the percentages of vanadium contained in the first to the second V/TiO2 SCR catalytically active composition, each calculated as V2O5, is from 0.05 to 0.75. Methods for the removal of NOx emissions from exhaust gases of internal combustion engines are also envisaged.