Abstract: The present invention relates to a method for the treatment of an exhaust gas comprising NOx, wherein the method comprises the step of subjecting the exhaust gas to an exhaust gas treatment system comprising, in order of the exhaust stream: (a) a first NOx storage catalytic converter (2, 2?); (b) a catalytic converter (3) for selective catalytic reduction (SCR) downstream of the first NOx storage catalytic converter; and (C) a catalytic converter (4) having oxygen storage capacity downstream of the SCR catalytic converter; wherein the exhaust gas treatment system is operated in alternating rich and lean phases, wherein the rich phase is terminated when the amount of reducing components leaving the first NOx storage catalytic converter is at least 0.