求翻译：现在许多大城市都有交通拥挤这一情况，堵车严重的时候就前不见头后不见尾的，就像一个小长城，还排放大量的二氧化碳，对空气造成了严重的污染。是什么意思？

Many large cities now have traffic jams this situation, traffic jam serious when the former but not the head not the tail, like a small Great Wall, but also emit large quantities of carbon dioxide on the air, causing serious pollution.
Know why this happens? Getting better and better social dev

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Now many big cities all have the traffic congestion this situation, traffics jams the serious time does not see after front not to see the tail, looks like a small Great Wall, but also discharges the massive carbon dioxide, has caused the serious pollution to the air.
Knew why can have this k

Many cities now have traffic congestion this situation, traffic jams before serious when it disappeared after the first tail gone, just like a little great wall, large amounts of carbon dioxide emissions on air cause serious pollution.
Do you know why this happens? as social development is gett

正在翻译，请等待...