very rightly said it was Nawaz Shareef scam ..
you need to locate the documents / owner who obtained the lease from Bank under taxi scheme. obtain an NOC from the bank to transfer the vehicle and apply for new registration plates.
if it is has clean documents & with private registration you need to clear all taxes at excise office in sindh. Taxes paid outside province of registration stand null & void.
while clearing the taxes you can simultaneoulsy apply for fresh registration book. There is no SMART card launched in SINDH because of top ppp leadership governing province of sindh are sponsors of criminals involved in vehicle theft, smuggling, and butchering vehicles preparing forged documents. If Computerised vehicle registartion cards are introduced they will die in misery spitting blood from every hole