If you look at all the criteria MHRD takes into consideration while ranking institutes, NIT Silchar is at par with most NITs but in terms of research, and infrastructure. The only parameter in which NIT Silchar was behind NIT Warangal was reputation and the difference was drastic. This affected the overall ranking of the institute in turn lowering the NT Silchar cutoffs.
I think the major reason behind its poor reputation is its remote location and the rumors related to it. It's falsely rumored to be in a Naxalite region and the exposure is believed to be minimal. The institute has a bad reputation, particularly in North India.
I have friends from several NITs and I have safely concluded that NIT Silchar is better than many but it's difficult to convince people of the same and the institute has a bad reputation.
To fix this problem, we need our alumni to be more active in portraying the right image of the institute. Additionally, the institute should hold more inter-college events and strive to build a reputation.