这项政策的实施是为了控制环境污染，因为塑料袋造成的污染已经成为都市环境的一大威胁。

This policy is carried out for controlling pollution since the pollution resulting from plastic bags has become a big threat to urban environment.

youdao

你说什么？大都市的环境污染对农村的树有影响？

Say what? Big cities affect the trees in the countryside?

youdao

大都市的环境污染对树有影响……毫无疑问。

Big cities, with all their pollution, have an effect on trees...... No doubt.

youdao