@pvish
When you play a video of something like snow, does it appear yellowish then too? If not, then its perfectly normal. Its got to do with the color temperature of the panel itself. Like AMOLED panels have bluish tint and other screens are reddish and so on.
So if you are only talking about yellowish tint in browser then its perfectly normal. But when watching videos or viewing pics with white color if white appears yellowish then you should get a replacement. If its fine in pics and videos then nothing to worry about.
Even Galaxy S2, S3 have bluish/pink tint. Most phones have such issues you can google for more info. So I would suggest take back the phone and relax if its limited to browser.
Its not a "fault" per se but normal behavior of the panel.
And yes if the yellowish tint is visible while playing videos/viewing photos as well then I suggest you make a post on Sony India Facebook Page ( Sony India NOT Sony Mobile India) they will get your problem solved