Furthermore,the air quality in cities is
often poor, due to pollution from traffic,
and the streets and public transport systems
are usually overcrowded.
在我知識範圍內（雖然很小）
due to是介詞
不能直接加上主詞(pollution + systems)和動詞(are)
應該用連接詞because才對
是句子錯還是我錯了？

and the streets and public transport systems are usually overcrowded 這句是另一個完整的子句 and太多非常干擾

原來不是錯誤。謝謝，我看懂了！

due to跟because of可以互相替換意思差不多。這兩個後面都是接原因，所以這句裡面pollution from traffic就是這個"原因"，要把它們看成一組而非分開的三個詞。如果是我我會這樣標點：Furthermore, the air quality incities is often poor due to pollution from traffic;and the streets and public transport systems are usually overcrowded. 這樣看比較順。