Water/petrol gushing sound from Optra underbody

Hi, I am noticing a peculier problem from past few days, i dont remember if this was there before, The problem is when ever i accelarate or brake in my Optra 1.6 i hear sound of water or petrol gushing, like under the right door, dont know if this was normal, i took full tank petrol last time, but the sound is still there. No petrol smell but, also even when i hit a bumper or pothole i get this sound like water hitting the shore, i checked my car of water bottles, but none is there in the car. There is no problem with the car otherwise, i can hear the sound only with windows up and AC off / 1 position. 1. Are there chances of rain water accumulating underbody? 2. Or is it normal petrol flowing sound. Optra owners please help, otherwise i have to take the car to sundaram motors which is bit far from my house.

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