Abstract: The present invention relates to a catalytic article for purifying an exhaust gas containing nitrogen oxides, which comprises a first region containing a vanadium-based SCR catalyst, a second region containing a metal-promoted molecular sieve catalyst, and a third region containing a vanadium-based SCR catalyst, wherein at least part of the second region is located downstream of at least part of the first region and upstream of at least part of the third region in the exhaust gas flow direction, provided that no part of the second region is located upstream of the first region or downstream of the third region. The present invention also relates to a method and a system for treatment of an exhaust gas containing nitrogen oxides by selective catalytic reduction using the catalytic article.