Which is considered a weakness of the city-level measures to tackle dirty air? ( )

参考解析：

细节题。根据题干关键词a weakness of the city-level measures及tackle dirty air定位到第三段第二句：That’s because they inevitably put the costs of cleaning the air on to individual drivers—who must pay fees or buy better vehicles—rather than on to the car manufacturers whose heating is the real cause of our toxic pollution.这是因为他们不可避免地把清洁空气的费用转嫁给那些必须支付费用或购买更好车辆的司机，而不是汽车制造商，因为他们的供暖是造成我们有毒污染的真正原因。选项A的They are biased again car manufactures.他们对汽车制造商有偏见，文中提到汽车制造商，却并未提到对其有无偏见，属于偷换概念。选项B的They prove impractical for city councils.这些措施对市议会来说是不切实际的。选项C的They are deemed too mild for politicians.他们被认为对政治家来说太温和了。定位段并未提到，属于无中生有。故本题正确答案选D。