China's capital, Beijing, has announced measures to combat worsening air pollution, state-run media report.
老年人一向被认为是最安全的司机群体。他们一般不会在交通高峰时段上路，发生事故的机率也比年轻司机小很多。可是越来越多的老年司机在英国被撤销驾照了，原因是什么呢？请听 Judith Moritz 的报道：
They include taking half of the city's four million private cars off the roads on days when there are serious levels of pollution.
Motorists over 70 are considered to be amongst the safest on the road。 Many avoid rush-hour and late-night driving and are said to cause fewer accident-related injuries than younger drivers。
The system will be based on a vehicle's licence plate - odd numbers will be allowed on the roads one day, even numbers the next.
But more of them than ever are being stopped from driving for medical reasons。 In 2011 just over 10，000 over-70s were banned because of their health。 By last year， that figure had risen by a third to nearly 13，000 drivers。
Motor vehicles are considered a major source of pollution.
The DVLA （Driver and Vehicle Licensing Agency） says it is not clear why there has been such a surge in the number of older drivers losing their licence on health grounds。
The new system will give out four different degrees of air pollution warning - blue, yellow, amber and red, Xinhua news agency reports.
Cars drive on a motorway towards Madrid, Spain December 28, 2016
Madrid has ordered half of most private cars off the roads on Thursday to tackle worsening air pollution, a first in Spain.