A wall-flow filter comprises a catalyst for converting oxides of nitrogen in the presence of a reducing agent, which wall-flow filter comprising an extruded solid body comprising: 10-95% by weight of at least one binder/matrix component; 5-90% by weight of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof; and 0-80% by weight optionally stabilized ceria, which catalyst comprising at least one metal, wherein: the at least one metal is present throughout the extruded solid body alone or in combination with: is also present in a higher concentration at a surface of the extruded solid body; is also carried in one or more coating layer(s) on a surface of the extruded solid body; or both.
