Is this dust inside Retina Display on my Macbook Pro 13 inch? I have a late 2015 13 Inch Macbook Pro with Retina Display, and here are the pics of that. Could anyone please suggest how do I get these spots of my screen?

Regards,
Bengalurean
Judging by your photo's this is not dust but the anti-reflective coating peeling of the screen.
As jksoegaard correctly states in the comments, apple has an extended warranty in place for this issue.
This article tells you more about it, and here it is mentioned on apple's forum.

You should contact your nearest apple service provider, they are very likely to replace your display for free.