Dont forget I lived in Karachi for the most of my life and only moved to the US recently, When living there I travelled on small motorcycles and my cheap car that ran on diesel fuel (super cheap 20 + km/lit).. Your argument is invalid because you want your cake and eat it too. It never works.
speaking of honesty - its an obsolete commodity in Pakistan now. Apparently all the nawaab population of Pakistan wants to roll in shiny new wheels (added chrome is a must if its eskalai) just for the heck of it and yet complain "petrol bohot mehenga hai" -- These same people dont give a damn to fuel when they are sitting in their cars with A/C running and engine idling while someone is shopping.. lol
Another point in honesty, where and when have you seen any business operate under a mandated safety guidelines, even hospitals are mopped with a dirty raggy mop with a pint of dettol and dirty water and call it perfect while the edges of the corridors are filled with mucky grease and other nasties.
another point.
You said its easy to implement CNG and put honest people in the inspections and safety while yet you do not want to blame illetracy because its a "majboori" - a bit of an oxymoron isnt it.
lets say proper CNG safety guidelines are mandated, which would say to only make CNG dispensers with at least a 1 sq/km blast radius of the battery bank (meaning out of human dwellings aka out of city), The vehicles running it will be subjected to arrest if the fuel tanks are tampered or damaged or EOL (5 years - means buy a new cylinder)
Car health and safety check including structural integrity (meaning denter/painter ustaad need to find a new profession), vehicle emmissions gear if found tampered would result in cancellation of the vehicle registration (meaning mechanic ustaad needs to go to school or close shop - leaving the big workshops around who will charge you "book time" money). Any illegal road hazard mods will result in arrest of the cars (car dekorashan shops will need to improvise) Motorcycles will also follow similar suit. Buses would require to have the proper seating dimensions for passengers and need to pass the comfort, safety, emmissions and road hazard standard too (meaning all Khan sb coach wala need to dump their POS)
NICE isnt it.
I dont think you will like it - It doesnt sound like Pakistan.
for a temporary solution that works, try to make private car pools. helps everyone and keeps the cost lower too.
btw - Ive seen a perfect bus system in Karachi go to hell (the metro coach) and also the famous green bus, during its time Karachi traffic was very fast moving towards a peaceful one. Till the inbred, born out of wedlock, illiterate, scum of human kind collectively known as the "transport association" killed it dead (literally blood and guts)