People burned out of their homes by the hundreds. Villages, even refugee camps, raked with gunfire. Men, women and children beaten and set ablaze by angry mobs. India, the world’s most populous country and home to the fastest-growing major economy, is now also the site of a war zone, as weeks of ethnic violence in the remote northeastern state of Manipur has claimed about 100 lives. Militarized buffer zones now crisscross the state, patrolled by local women — who are seen as less hotheaded than men — and the thousands of troops who have been sent to quell the fighting,...