As while in the every day exercise, once the travellers vacation from 1 nation to a different, they may bring the air pollution from a single place to another. The plane would launch the waste gases all around the planet and could not be limited by borders. Thus, the environmental https://nimmansocial.com/story1640611/%E5%8C%97%E7%BE%8E%E4%BB%A3%E5%86%99-for-dummies