Could you be a bit specific as to what you really want to know?
In Pakistani civil bureaucracy, there 22 Basic Pay Scales (BPS) with the Grade 22 being the highest. Grades 1 - 4 are for lower office staff, such as peons, drivers, foot constables etc. Grades 5 - 16 are for educated workers who mostly do the clerical work etc, however, this is a broad category and most workers belong to this band. Most of the clerks, lower district officers, superintendents, govt primary/secondary school teachers, police officers upto the SHO level etc, belong to this cadre. Then there is the superior service comprising of officers from grades 17 to 22. Hiring for such is *usually * through a tough exam called the civil service exam (CSS) or a slightly easier version, PCS. However, the government also hires and inducts people directly into grades 17 - 22 through other means.
CSS is further divided into different groups (cadres) such as district management, foreign service, police, customs, income tax, office management, secretariat etc, and having joined the civil service through CSS, most officers rise to the highest levels of civil bureaucracy (federal secretaries, director generals and chairmen of ministries, divisions and boards etc). Again, all CSS officers start in grade 17 and eventually rise as high as grades 21 and 22.
thanks a bunch