Before I proceed further, I urge you to read the 'methodology' section in each of these publications; you'll find quite a lot in there that should tell you to not take these rankings seriously. If you are in the mood for some serious fisking, go read Arunn's and Madhukar Shukla's posts from three years ago!
The rankings are typically for colleges offering programs in engineering, medical, and law; some of them include rankings of programs in hotel management and mass communications -- and Mint even does fashion!
College rankings are not at all a useful way of thinking about institutions. But the ratings they receive from these magazines have some -- but only some -- value. This is because small differences in ratings may mean big differences in rankings, especially when one gets past the top 10 or the top 20 -- take, for example, the Outlook's list of engineering colleges; a difference of just 10 or 11 percent (767 and 689) separates the college at No. 20 from that at No. 40!
Even the ratings have their own flaws; many of them are based on the so-called 'perceptual' scores -- a fancy term for surveys of faculty, students and / or recruiters; they are susceptible to systematic biases -- selection bias being the major one. And then there is the possibility of "gaming the system" [with Clemson's and University of Florida's efforts being just the most recent examples from the US].
In the absence of a mandatory, unimpeachable accreditation system -- and the one in India fails on both counts! -- all we have are these highly flawed methods employed by news outlets, which outsource this operation to survey organizations whose expertise is not necessarily in higher education.