Well guys, lets get technical here
HP (horsepower) determines the max power output of car, that is to say roughly you can determine the performance, but you cant just say that for example, a 63 Hp is better than 52 HP. There are a lot of factors like torque curve of the engine, and most importantly, the weight of the car. If a car is 82 HP, 1.3 Litre car, its weight would be higher than say a small car with 63 HP. And the torque the engine produces will also determine acceleration at higher RPMs.
For the figures, they are in KW and of Joy in HP. 63 HP joy is the Pakistani version with 1.0 Litre engine. The figure for city shows 57 which is in KW. The HP of city is approx 77.
IMP: just for approx calculation of performance, if you know the weight of car (plus driver at least!), divide the weight with given Horsepower value, you will get rough time in seconds of the time the car takes to accelerate from 0 to 100 KM/H. E.G, if a car (like City) is 77 HP and the weight is around 1100 KG, divide 1100 by 78 and you get 14.2 seconds. Hope this helps