Official cars garaged if Beijing air worsens

 BEIJING, Dec. 14 (Xinhua) -- Construction is to be suspended and use of official vehicles limited in cases where Beijing air quality plummets¹ to "extremely bad," under a new rule on curbing³ air pollution.

The rule, to be enacted⁴ on Jan. 1, 2013, categorizes air pollution as "bad," "seriously bad," and "extremely bad" -- depending on a basket of indexes that include measurements of both fine and coarse air particles and ozone⁵ levels, meteorological officials announced on Friday.

Yu Jianhua, an official with the Beijing meteorological bureau, said when pollution is 'extremely bad,' work on construction sites will be suspended, heavy-polluting factories will be ordered to cut emissions⁶, and 30 percent of cars assigned to the Party and government officials pulled off the road.

The level of air pollution in Beijing has not been optimistic over the past few years. The city's sky is often shrouded⁷ by yellowish smog.

To curb² pollution, the government has introduced a spate⁸ of measures including moving heavy polluters away from urban districts. It also started to use PM 2.5, a measurement of smaller air-borne particles which experts say can be more dangerous to human health, to accompany PM 10 to gauge⁹ pollution.

1 plummets   

v.垂直落下，骤然跌落( plummet的第三人称单数 )

参考例句：

• As a result, blood sugar plummets, sometimes even going below the baseline. 结果，血糖浓度迅速掉落，有时甚至落于基线之下。 来自互联网
• State and local governments could continue to back as tax revenue plummets. 由于税收的直线下降，州和地方政府可能继续削减支出。 来自互联网

2 curb   

n.场外证券市场，场外交易；vt.制止，抑制

参考例句：

• I could not curb my anger.我按捺不住我的愤怒。
• You must curb your daughter when you are in church.你在教堂时必须管住你的女儿。

3 curbing   

n.边石，边石的材料v.限制，克制，抑制( curb的现在分词 )

参考例句：

• Progress has been made in curbing inflation. 在控制通货膨胀方面已取得了进展。
• A range of policies have been introduced aimed at curbing inflation. 为了抑制通货膨胀实施了一系列的政策。

4 enacted   

制定（法律），通过（法案）( enact的过去式和过去分词 )

参考例句：

• legislation enacted by parliament 由议会通过的法律
• Outside in the little lobby another scene was begin enacted. 外面的小休息室里又是另一番景象。 来自英汉文学 - 嘉莉妹妹

5 ozone   

n.臭氧，新鲜空气

参考例句：

• The ozone layer is a protective layer around the planet Earth.臭氧层是地球的保护层。
• The capacity of ozone can adjust according of requirement.臭氧的产量可根据需要或调节。

6 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

7 shrouded   

v.隐瞒( shroud的过去式和过去分词 )；保密

参考例句：

• The hills were shrouded in mist . 这些小山被笼罩在薄雾之中。
• The towers were shrouded in mist. 城楼被蒙上薄雾。 来自《简明英汉词典》

8 spate   

n.泛滥，洪水，突然的一阵

参考例句：

• Police are investigating a spate of burglaries in the area.警察正在调查这一地区发生的大量盗窃案。
• Refugees crossed the border in full spate.难民大量地越过了边境。

9 gauge   

v.精确计量；估计；n.标准度量；计量器

参考例句：

• Can you gauge what her reaction is likely to be?你能揣测她的反应可能是什么吗？
• It's difficult to gauge one's character.要判断一个人的品格是很困难的。