Hello,
Although it's an old thread I had some recent encounters with the Police regarding my car tints so thought to share the experience with fellow citizens on "How to not Victimized by Police"
There is no concrete law in Pakistan but a penalty exists which is applicable within the Jurisdiction of Punjab but at no point, it provides a further explanation or directions regarding tearing/removing tints from private property.
Per THE PROVINCIAL MOTOR VEHICLES ORDINANCE 1965, Twelfth Schedule Violations and Penalties. Driving a motor vehicle with tinted/ covered glasses has a fine of Rs.500. This is applicable on Cars and Jeeps Only. Bikes and commercial vehicles are exempt from it.
As far as a percentage is concerned, there is no specified term used in law regarding the percentage which gives an open space to go for 100% 
Now in order to exercise the fine, the officer must either belong to Punjab Excise and Taxation or City Traffic Police Officer. Punjab Police has no right to exercise this Law and threaten you with "Gaari Baand Ho ge"
So next time, If you are stopped by the Police, Please exercise your fundamental right to inquire and if they drag you with a lame game, simply show them a copy of the Punjab Laws. Sharing Ordinance below in the link for convenience.
http://punjablaws.gov.pk/laws/189.html
Regards,
Your very own Fellow Citizen & Proud Legal Practioner.