Look, I'm not giving my personal commentary, I've showed you the source from where I had got the information and frankly, I would prefer those articles over a story-telling by a random guy. May be I should have quoted the entire para:seriously even i being living on that area giving full explanation still being in denial i dont no why???
And for last time NH 31 is not pron to landslide or flood because that area is not mountainous ....you are mixing with NH31A which is in Darjeeling area are pron to landslide
All land trade between North-East India’s 40 million denizens and the rest of the country traverses the Siliguri owing to the lack of a free-trade agreement between India and Bangladesh. In 2002, Nepal, Bhutan, and Bangladesh joined India in discussing a proposal to create a free-trade agreement that would have facilitated the movement of goods across the Siliguri corridor, but no such agreement has been established. Further reinforcing the strategic precariousness of the region is the fact that a single-line railway is all that carries rail-based freight across the Siliguri. The harsh topography of the region makes the railway and roads subject to damage from frequent landslides and natural disaster; India’s North-East is known for its record-breaking levels of rainfall.
Geography’s Curse: India’s Vulnerable ‘Chicken’s Neck’ | The Diplomat
If you really want to refute me, come up with a credible source like the one I've posted.