NATHU LA, India—Indian army enlisted man Jitender Singh Sehrawat has had a few close calls.

When lightning tore through the roof of his bunker at a high-altitude post on the Chinese border one recent afternoon, it blasted a hole in a metal mess plate lying feet from where he was standing. Miraculously, Mr. Sehrawat says, he and his squad mates were unharmed.

He...