Tablespace is 99%

Dear guyz

Please help me regarding the table space issue, as I don't have any idea or any guidance that how to free up some space in tablespace.

When i go to System --> Database --> tablespace summary. 

I see the following condition of my tablespace. 

I deleted all archived incidents but no joy. Please help me. its urgent.

Thanks

Regards

Zuhaib Siddiqui