One 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