@mahmood is right
I had once problem similar to this with my city idsi 2004. on little bumpy road at abt 80km, the car would take a left. but on smooth road it was fine. I checked it to many of our drivers, but they said its ok (but i was not convinced), after that i went to honda guys, at first glance they always says that these are bushes. I said to change the bushes. They have to remove the front suspensons for that, and after that it was discovered that the left damper has expiered. It would come back bak to its position. (Suspension=damper+coil spring). So my car weight was on spring. They normally sells suspension in pairs so i went for 2nd hand suspesnion + bushes + some warrenty etc that cost me 22k (although if i had bought the pair of damper it would be good too). I brought the faulty suspension and the good one with me.