Why sun appears red

A difficult question to answer but I will give it a try...

When the sun rays comes down to the earth it passes through different layers of the atmosphere and on the way lights of lower frequencies like red has the less chance to get blocked then the light of higher frequencies like blue. Therefore any observer on Earth sees the sun as red rather than any other color like blue.

good one ajay. It looks that you have given correct answer.

It's difficult to explain, but you have answered ajay, thanks

The right reason is - red light is getting less scattered compared to other colours in white light.Also red can travel long distances.