this is a little high - and if you say it decreases when you are in speed that means that either the radiator fins or the condenser fins are clogged with dirt. It can also be a bad radiator fan, make double sure that the fan shroud is SEALED at the radiator, it should not allow any air to be sucked in from the sides, use foam strips to seal it completely.
If the fan blades are warped get a new fan. Honestly throw away the garbage thaka huwa fan that PS gives with the mehran and get a proper high CFM fan or at the very least the condenser fan from a Hyundai Excel taxi.
Are you positive that the pipe that carries coolant to the waterpump (waterbody) is not plugged with rust flakes, because if it is then coolant would never circulate fully through the radiator.
Finally make sure that when you fill the radiator you keep the cap open till the engine warms up and the fan switches on, then squeeze the pipes to get rid of any air in the system because that air can cause local boils and cause temperature spikes like this.
