在100个人口最多的城市中，22个为无烟城市。

Of the 100 most populous cities, 22 are smoke free.

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拥有434万人口的悉尼是澳大利亚人口最多的城市。

With an estimated 4.34 million residents, Sydney, shown on Earth Day 2008, is Australia's most populous city.

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在世界100个人口最多的城市中，22个是无烟城市。

Of the world's 100 most populous cities, 22 are smoke-free.

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