Dear Make sure it says distilled water and not battery water on the label.
A bottle of local battery water may have some acid added to it which can damage the metal of radiator system or even react with the coolant creating floating salts.
Plain water can be used in Pakistan environment but then need to do radiator service every spring and ready to replace radiator 3-5 years. Else use some quality coolant with distilled water for a radiator service interval of 3-5 year and radiator life of minimum 10 years. Rest do the maths!
My car (riyadh) had a leakage in 2009(winter 5 C Ambient). I got it fixed but started using tap water in it on suggestion of a desi mechanic saying water is better heat exchanger. All of a sudden my car started to hate me.
In 2010 i had to repair my ac 6 times(2 times sanc phooli, pressure release valve, multiple ac leaked pipes and noozles sepeartely during the year 2010 and had to replace head gasket eventually (after been stranded on a highway for 3 hours). After going through all this trouble i went to radiator service beginning of summer 2011 (replaced it properly and started to use coolant) now our romance is back on track like the days i bought it.