proper measures must be taken to limit the number of foreign tourists and the great efforts should be made to protect local environment and history from the harmful effects of international tourism
应该采取适当的措施限制外国旅游者的数量，努力保护当地环境和历史不受国际旅游业的不利影响
以上为机器翻译结果，长、整句建议使用 人工翻译 。