Hi Sai, it looks like there is noise in the sky and the horizon seems to fall apart where it meets the sky. It could be from over sharpening or it could be heat waves from the distance but that's probably what they would consider a technical issue.
There is noise in the sky, the overall exposure isn't good, it is rather oversaturated, and the general composition isn't good - the horizon isn't straight. You also have a blue band/bar/out of focus bit across the bottom of the picture.
Have a read of this. It's a brief guide on image quality:
Just one tiny observation. Looking at the tree and poles, they seem upright, meaning the horizon should be fine. It appears the landscape has a slight slope.