All modern common rail diesels such as the smart cdi (that I have) already use EGR, and have oxidation catalysts, but that alone does not solve the NOx problem. It reduces it, but the Mercedes-Benz BluTec system will bring it totally under control.

2008 Mercedes-Benz B 200
2005 smart fortwo cdi pulse cabriolet
1966 Peugeot 404 Coupé Injection
1989 Peugeot 405 DL