Thanks to all for the valuable input... This is my first CG125 so I am not sure about all the things that is why I asked... Previously I have done some excursions on my brother's GS-150 which is really a superb bike for hilly areas as well as some off roading...
Anyways from your suggestions I have concluded that any one of the following could be wrong with my bike...
1) Air-Fuel mixture is not set properly... I mean it is set for Islamabad's altitude or even lower and when I gained altitude and the air became thinner the bike started to under-perform. To correct this problem should I increase the petrol or decrease it?
2) Some problem with the fuel itself... like some residue, water etc. mixed. Although chances of this are remote as on the same petrol the bike performed very well in Islamabad.
3) The electrical is not giving the desired amount of current...Although a brand new bike should not give such a problem but any how I will get it checked...
4) Maybe some Kala Jadoo at Murree Side...
Anyways if such a problem arise is it OK for a novice like me to adjust the fuel settings using the Screw? What should one see while doing it?