Original sentence: China has been criticised for having built the railway to strengthen its political control over Tibet.In particular, Humans Rights Watch and the International Campaign for TIbet have alleged that the railway will marginalise Tibetans in the Tibet Autonomous Region by encouraging further immigration from the rest of China.They have also expressed concerns that the Chinese government will use the railway to strengthen its military presence in the Tibet Autonomous Region and to further exploit Tibet's natural resources and damage its environment
Edited sentence: It is alleged by these opponents that the railway will encourage further immigration from the rest of China, reducing the proportion of Tibetans in the Tibet Autonomous Region.Opponents of China's Tibet policies claim that the railway was built to strengthen its political control over Tibet.Tibetans independence supporters have also expressed concerns that the Chinese government will use the railway to strengthen its military presence in the Tibet Autonomous Region and to further exploit Tibet's natural resources and damage its environment