In Xinjiang, the authorities have upgraded 15 airports in the last five years. Seven of them are military or dual-use facilities

According to the research paper, "one such airport is Hotan Airport, a major dual-use airport located approximately 240 km from the western portion of the Line of Actual Control (LAC)".

Significantly, it says, "less than 5 km southeast of the main airport area, a surface-to-air missile (SAM) complex is being upgraded, enhancing the air defences at the airport and surrounding areas".

There is serious investment involved in developing road and rail infrastructure in the two regions. According to official figures, "Tibet's highway system grew 51 per cent between 2015 and 2020--from 7,840 km to 11,820 km--faster than the growth rate of any other province, region, or municipality". Xinjiang's network of highways has expanded at a fast clip as well, "growing from 17,830 km in 2015 to 20,920 km in 2020".

The build-up is significant because not only are the Xinjiang and Tibet regions far-flung from China's industrial east coast, they also border 11 countries with most of whom China has running disputes.

Xinjiang is important to China because of its Belt and Road Initiative (BRI) project and its intention to re-create the ancient Silk Road in order to find a new land route for Chinese products to enter Europe.

Xinjiang occupies a central position within the BRI and serves as a key link between China and its western neighbours, reported Tibet Press.

China has also beefed up "security cooperation with bordering countries--including Tajikistan, Afghanistan, and most recently Kazakhstan--with the aim of enhancing their domestic security and fending off instability that could spill over into China".

Internally, China is concerned that either inimical foreign powers or local insurgents might foment trouble in Tibet and Xinjiang.

The movement for independence by the Tibetan people and the protests of Xinjiang's Uyghur Muslims over Chinese oppression are the reasons for worry. What is more, both regions are autonomous regions in China with substantial ethnic minority populations, reported Tibet Press.