For a while, India and China even claimed to have finally settled their dangerous border dispute. If they ever had a deal, it seems that deal is in doubt.
The land in question is the northernmost Indian state of Arunachal Pradesh and the Himalayan region of Aksai Chin. In new Chinese passports those regions are shown as belonging to the People's Republic. India has responded by stamping the Chinese passports with its own map showing the regions as Indian.
China and India went to war along this border in 1962. Since then India has claimed China has illegally occupied its territory in Aksai Chin while China has claimed the state of Arunachal belongs to it.
There is a great deal at stake up here including access to freshwater resources both countries deem vital.