What surprises me is that the discussion here is taking the original article at face value. Sure, the Indian govt is citing national security as the reason for the ban. But take a slightly cynical view, and focus your attention on this sentence:

"Jayanth Kolla, an analyst at research firm Convergence Catalyst, told TechCrunch the move was surprising and will have huge impact on Chinese firms, many of which count India as their biggest market."

That's the real reason. This is just posturing between two neighbouring countries who are currently involved in a border dispute. There is already a lot of military posturing, a lot of diplomatic posturing and now a lot of market posturing, which includes the Internet.