Anti pollution fault light on my 206 . ?

I have just topped up my peugeot 206 engine oilfor the first time since having it ...... before a long journey next week , however when i restarted the engine i had the anti pollution warning sign come on along with the little engine warning sign on my dash .i am now scared to drive it . The oil i used was the correct oil ....and i cant seem to work out what the problem is ? if some one could give me some idea about how to fix this problem or some advice it would be greatly appreciated thank you .