In 1950 the peoples liberation army on orders of the Central Committee of the Communist party invaded the state of Tibet which was earlier an independent state and was recognized so by the British. It acted as a buffer between British India and China. The Indian border with Tibet and de facto independence of Tibet was recognized at the Simla conference of 1913.
When the British left india in 1947, India became the successor state to the British. Nehru in his zeal gave up all rights in Tibet and tried to be friends with China. The Chinese paid Nehru back by attacking Tibet and in a swift campaign overran the state. Sardar Vallabhbhai Patel was keen for an Indian intervention to rescue Tibet, but Nehru by a twisted logic did not intervene.
Once the Chinese took control over Tibet they began a steady integration of the state with China. They also planned to kidnap the Dali Lama and take him to China, but by a ruse he escaped in the dead of night from Lhasa to India. The Chinese discovered his absence after 2 days, by which time he was close to the Indian border. The Dalai Lama was given asylum in India and along with him thousands of Tibetans also escaped to india.
At a conservative estimate more than 2 million refugees have escaped to India from Tibet. After the 1962 defeat at the hands of China, the Indians in conjunction with the USA tried a rebellion against the Chinese. This was called the Khampa revolt, but it failed because of a ruthless execution by China. Thousands of Khampa rebels were shot dead and the movement petered out.
The Chinese also forcibly married Tibetan nuns to Chinese soldiers and opened Tibet to settlement by Chinese. Their plan was to try and change the demographic composition of Tibet's population. The Chinese refused to allow any Tibetan from India or the Dalai Lama to enter Tibet and for 60 years have refused to negotiate with him,. they have also put pressure on countries not to receive the Dalai lama and to some extent have been successful. In fact the world now does very little for Tibetan independence and that includes the USA, as they are scared of political, military and economic might of China.
However the Chinese have brought in a degree of economic progress in Tibet and an example is the high speed pressurised train from China to Lhasa. The Chinese crush dissent in Tibet with an iron hand and many pro independence agitators are jailed for over 20 years.
In contrast India has handled the Kashmir problem with kid gloves. The Indian state has accepted a separate flag and constitution for Kashmir and the separatists who form the Hurriyat are given protection and allowed to roam free. In addition Article 370 is incorporated in the Indian constitution giving special status to Kashmir and no Indian from another state can settle in there. The state of Kashmir is thus effectively insulated from the rest of India.
What a contrast with China's handling of Tibet. .The way the Indian leadership is moving a stage may well come when we hand over the Muslim valley to Pakistan, for the simple reason the political leadership is unable to take hard decisions on Kashmir like abrogating article 370 and junking special status for kashmir. How can the state integrate with India if these trappings remain?