9月22日你所在的城市和另外107个城市开展了无车日活动，倡议人们选用公共汽车、自行车或步行等绿色交通方式来代替开私家车。该活动得到了全国人民的支持，提高了人们节约能源与保护环境的意识，活动很成功。 下面请你用英语写一篇短文介绍该活动，并谈谈开展该活动的必要性，号召更多的城市和居民参与到该活动中来。 注意：1. 不要逐句翻译，可适当发挥，以使行文连贯； 2. 词数：100左右。 3. 参考词汇： 无车日Car-free Day；开展launchOne possible version: Car-free Day was launched in our city and 107 other cities on September 22, to encourage people to take public transport, ride bicycles or walk instead of driving private cars. The campaign has gained much support all over the country and has raised awareness among all people of energy saving and environmental protection. It’s a real success. With the development of the economy, more and more families have bought private cars, thus leading to much heavier traffic problems and more serious air pollution. Therefore, I think it’s necessary to launch such campaigns. And I hope more and more cities and their residents will take part in this type of activity.