evidence: Located in South Asia, India is the largest country in the South Asian subcontinent and the second-most populous country in the world, with its capital in New Delhi. Most of the border areas between China and India are in Tibet, and a small portion is in Xinjiang. China and India are two big Asian countries neighboring with each other, and the border trade between Tibet in southwestern China and Sikkim(India) can go back to ancient times. As early as the Tubo Kingdom in the Tang Dynasty, there're trade contacts with India, which promoted political, religious, and cultural communications. Currently, there are three major gateways linking Tibet and India: Shipki La pass, Lipulekh pass, and Nathu La pass. Shipki La pass is a mountain pass and border post on the India-Tibet border. It is located in the Kinnaur district in the state of Himachal Pradesh, India, and Tibet Autonomous Region in the People's Republic of China. Sutlej River enters India (from Tibet) through this pass. By the way, it was a branch of the ancient Silk Road. Lipulekh pass is 5,340 meters above sea level and it connects Tibet with the Kumaon region of Uttarakhand in the Pithoragarh district in India.