I have no idea about PSO diesel quality parameters, neither past nor current. I have only read/heard that the local diesel has high sulfur content, or is of poor quality etc etc.
If the new/current quality of diesel is similar to what is available in Europe, it is good news.
EDIT
Since Jan 2017, PSO is importing euro 2 compliant diesel with 500 ppm Sulfur content limit, which in previously available diesel was 5000 ppm.