The problem is caused by relative positioning of .parallax
Remove relative positioning from this and it works fine.
.parallax {
background: url(../img/worldImg.jpg) repeat fixed 50% 0px;
margin: 0 auto;
width: 100%;
position: relative;
box-shadow: 0px 0px 20px #000 inset;
}
I found the problem but I am not sure why it is happening.