This is bad news for car owners, current and potential.

To cushion the blow, drivers can use their vehicles less or change their habits. The cost-conscious will opt for a more economical model.

But sadly there may be a limit to how economical one can be, depending on where you live.

In Beijing, if your car's engine displacement is 1 litre or less, you are not permitted to drive down Chang'an Avenue, nor through the centre of the city bounded by the second ring road.

In Shanghai cars with a 1.2-litre engine or smaller are prohibited from using the city's viaducts.

One simply cannot get a licence plate for a 1-litre car in Suzhou.

While one can drive a 1-litre car in Guangzhou, the city's main trunk roads are off-limits.

Across China, more than 80 cities have installed restrictions on small vehicles.

Small cars are usually more economical. That is common sense. They consume less oil, emit less hazardous exhaust gases and take up a smaller amount of parking space.

But why do our governments find them intolerable? Are they out of their minds?

This is exactly what we have had difficulty figuring out.

We are the world's second largest consumer of oil and our appetite keeps growing.

To fuel our economy we have to buy from overseas. Oil is one of our premier imports. But we all know heavy reliance means large risks.

An effective way to lower our vulnerability to uncertainties in external oil supply is to use less of the fuel.

One of the most inspiring recent developments in the country is the idea of saving resources. From the capital to small, remote communities, officials have the same slogan on their lips - build a thrifty society.

While officials of all ranks make elaborate promises to execute the so-called scientific perspective of development the most fashionable political catchphrase the media is tirelessly showing the public the best ways to save resources.

Accounting for the most rapid sector of growth on the nation's energy bill, vehicles should be no exception. Consider the relatively low proportion of car owners in China and the increasingly popular and accessible dream of owning one's own set of wheels. Many are itching to start their life in the fast lane.

Automobiles account for more than a third of our entire oil consumption. By 2020, when the country is expected to have between 130 million and 150 million cars on the road, it will be two-thirds.

People want a new way of life. The government has its heart set on automobile manufacturing as a new growth point for our economy. But we are short of oil.

The most logical solution is to let people buy smaller, more economical models. The State should encourage the development of low displacement vehicles.

The national plan for mid- and long-term energy conservation also proposes to "nullify all unreasonable rules that restrict the use and operation of automobiles featuring low oil consumption, low engine displacement and low emissions."

But such policies have turned out to be impotent in the face of local bureaucrats' determined rejection of energy-saving cars.

Despite efforts they have taken to save water and electricity, we are curious to know why so many local governments stick with irrational restrictions on small cars.

It is bewildering that almost all such restrictions were installed without proper procedures or convincing arguments. If they lack legitimacy, why should they stay?

We are tired of excuses such as small cars cause more congestion and are not safe. The excuses are too porous and ridiculous to deserve serious counter-argument.

We sense hypocrisy in the contrast between the lip service paid to becoming more economical and the recalcitrant hostility towards small cars.

The policy-makers have to be serious about such a credibility test.