The world's most populous nations, both nuclear powers, are locked in a deadly face-off over a contested border high in the Himalayas. Tensions in a decades-old dispute between China and India have boiled over recently, with 20 Indian soldiers dying under murky circumstances in the treacherous Galwan Valley. Stephanie Sy reports and talks to Alyssa Ayres of the Council on Foreign Relations. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders