Fitness certificate is for commercial vehicles be it passenger or of any other application.
Remember few point if & when confronting traffic police [ normally the poor fellows salute you for payment of Rs. 20 from bikers and Rs. 50~100 from sedan cars , they have no BA LLs to wave a SUV ]
traffic police can only "check" 1. vehicle registration papers, 2. tax payment 3. driving licence. absence of above 3 plus any other violation is ticketable offence subject to penalty.
[ Radio licence is no longer required because monoply of RADIO PAKISTAN does not exist any more. same is case of TV license fee which PTV has smartly linked to utility bills and extortion is taking place from every one of us with Electricity connection and paying bills, case is in court for past 27 years. ]
I strongly recommend keeping cool and polite respectful attitude while dealing with traffic police, 2 cents !