I’ll have to explain a few things to explain that.
First of all, tanks have the thickest armor at the front, and they have a thing called the frontal armor arc. basically, tanks designers design tank turrets and hulls in such a way that the thickest armor doesn’t just cover the narrow front of the tank but also extends a certain amount to the side of the tank. Notice in this image of a T90S turret how the front of the turret is not flat but angled so the frontal armor arc extends on each side of the tank. This design feature is present in both the T72 and the T90S as well as the T80UD, meanwhile the Al-Khalid and the VT-4 have a nearly flat turret front, meaning it’s armor is only at the front with the entire side of the turret vulnerable to enemy fire, this is somewhat remedied by adding ERA to the turret side as the Al-Khalid and VT-4 do, but Al-Khalid has older ERA so this isn’t going to help it that much, VT-4 at least has much better ERA with better coverage on the side of the turret, but this design flaw is still there. Arjun has these design flaws too.
.
View attachment 828661
A similar strategy is applied to tank hulls, where the first 1/3rd or 1/4th of the tanks side may have thicker armor than the rest. Or may have some sort of additional armor like ERA on the side of the tank. While no tank in South Asia has proper side hull armor for the entire tank, The T90S and the T80UD at least employ additional armor or ERA on the first 1/3rd of the tanks side. Al-Khalid and VT-4 have just their normal hull armor on the entire side of the tank, which is not that thick at all and is a massive weak spot. This is also surprising because Al-Khalid was initially deployed with similar 1/3rd armor coverage as T80UD and was even tested with a full side armor kit, but neither was ever put into service.
This image shows why having that 1/3rd side armor can be very useful, although it is an outdated example as it’s using a WW2 tank with no sloping armor, But disregard that for this example.
View attachment 828668
So what I mean to say is, that while Pakistani/Chinese tanks have armor that may be as effective, if not more, than the Indian/Russian counterparts, their design is very poor, with all of this armor being focused on the front of the tanks and no emphasis given to side armor, this is especially inexcusable in the case of the VT-4 which has the thickest front armor of any tank in the region and should have proper armor covering its entire side like T90MS or other modern tanks but has only thin steel on its side.
In short: from the front, modern Pakistani tanks are generally better protected than modern Indian ones (only talking about 3rd Gen stuff here), but Indian ones have better side armor simply due to their better russian design philosophy, however they’re not ahead not by much because of their age.
Indian tanks employ much poorer ammo when compared to Pakistani tanks, so they’ll have a hard time penetrating Pakistani armor in general, While PA tanks don’t have this issue. However the most prevalent threats to armor these days aren’t other tanks, it’s infantry, and that’s where side armor is important. IA employs a lot of modern ATGMs and AT weapons that will be very deadly to PA tanks if they can get a shot at the side.