An exhaust gas aftertreatment device (10c-e) for purification of exhaust gas emissions wherein said exhaust gas aftertreatment device (10c-e): • is arranged in an exhaust gas passage subsequently of an internal combustion engine, • is enclosed by an encapsulating portion of the exhaust gas passage, • comprises a first catalytic substrate and a second catalytic substrate, wherein ∘ said first catalytic substrate is arranged upstream of the second catalytic substrate, wherein ∘ said first and second catalytic substrates (30, 40) are arranged such that respective catalytic substrate (30, 40) covers a majority of respective flow cross sectional area of said exhaust gas passage, and wherein ∘ said first and second catalytic substrates (30, 40) are extending a respective length in a flow direction of said exhaust gas passage, and wherein said exhaust gas aftertreatment device further • comprises a reductant injecting device, and • a pipe extends in said flow direction of said first catalytic substrate such that said pipe provides a passage through said first catalytic substrate, wherein ∘ said pipe comprises an obstructing portion arranged such that said obstructing portion covers the cross sectional area of said pipe such that a difference in back pressure is obtainable between said pipe and said first catalytic substrate, and wherein • said reductant injecting device is extending through said encapsulating portion and into said pipe, such that reductant is injectable within said pipe, said pipe comprises circumferential perforations along at least a portion of the length of said pipe, wherein said perforations enables exhaust gas to flow into or out of said pipe through said perforations, characterized in that the first catalytic substrate extends along the pipe in such a way that the first catalytic substrate is located radially outwards of the circumferential perforations of the pipe so that the perforations enable exhaust gases to pass through a lateral surface of said pipe and, depending on the pressure difference between the exhaust gas in the pipe and the exhaust gas in the first catalytic substrate, enable exhaust gas to pass said lateral surface either from said first catalytic substrate into said pipe or from said pipe into said first catalytic substrate. • is arranged in an exhaust gas passage subsequently of an internal combustion engine, • is enclosed by an encapsulating portion of the exhaust gas passage, • comprises a first catalytic substrate and a second catalytic substrate, wherein ∘ said first catalytic substrate is arranged upstream of the second catalytic substrate, wherein ∘ said first and second catalytic substrates (30, 40) are arranged such that respective catalytic substrate (30, 40) covers a majority of respective flow cross sectional area of said exhaust gas passage, and wherein ∘ said first and second catalytic substrates (30, 40) are extending a respective length in a flow direction of said exhaust gas passage, and wherein said exhaust gas aftertreatment device further ∘ said first catalytic substrate is arranged upstream of the second catalytic substrate, wherein ∘ said first and second catalytic substrates (30, 40) are arranged such that respective catalytic substrate (30, 40) covers a majority of respective flow cross sectional area of said exhaust gas passage, and wherein ∘ said first and second catalytic substrates (30, 40) are extending a respective length in a flow direction of said exhaust gas passage, and wherein said exhaust gas aftertreatment device further • comprises a reductant injecting device, and • a pipe extends in said flow direction of said first catalytic substrate such that said pipe provides a passage through said first catalytic substrate, wherein ∘ said pipe comprises an obstructing portion arranged such that said obstructing portion covers the cross sectional area of said pipe such that a difference in back pressure is obtainable between said pipe and said first catalytic substrate, and wherein ∘ said pipe comprises an obstructing portion arranged such that said obstructing portion covers the cross sectional area of said pipe such that a difference in back pressure is obtainable between said pipe and said first catalytic substrate, and wherein • said reductant injecting device is extending through said encapsulating portion and into said pipe, such that reductant is injectable within said pipe,