Were it not for the news that Guangzhou is to lift an 8-year-old ban on small vehicles, many may not easily believe that there is such a restriction in the southern metropolis.

In fact, as early as 2001, the city stopped issuing licenses to sub-1,000cc vehicles, and denied those already licensed access to specific sections of the urban road network. One year later, such vehicles from other places were prohibited from entering the city proper. Which has been the strictest and most complete restriction on small automobiles in the country.

Even Beijing, where image-conscious municipal administrators betrayed a marked distaste for small cars, had not been so strict.

That indeed is a mismatch with the city's popular image of being in the vanguard of market-oriented adventures. The environment aside, discrimination against small vehicles based on engine displacement is anti-market.

The municipal authorities in Guangzhou did have their own reasons when they imposed the ban in 2001. Such cheap, small vehicles add to traffic congestions, are more vulnerable to technical problems, and may cause more serious pollution - all of which sound untrue today. Some home-made low-end small vehicles may have been lousy and polluting some years back. But, at that time, the bigger ones were not any better. Nor is it fair to blame a traffic jam on small automobiles alone.

What we know for sure is that traffic congestion is more often than not the result of awkward management. And, that, under similar technical standards, vehicles with higher engine displacement discharge more waste gas into the atmosphere.

The real purpose of Guangzhou's discriminatory policy reportedly was to raise the threshold of private vehicle ownership. The urban planners there wanted to postpone the popularization of family cars by five years. They were so determined that even after the decision-makers in Beijing woke up to the folly of such an approach and turned to encourage low-emission small vehicles and appealed for elimination of discriminatory policies in 2006, the city held on.

But such a threshold has proved too low to work the magic. Every single day, the city sees 1,000 new family vehicles on the road.

Except for leaving local residents seething with a sense of injustice, the ill-conceived policy did little to justify its masterminds' motivations. Its revocation was long overdue. Even so, it is worth celebrating. After all, they have finally come to terms with reason and decided to correct an obvious anomaly.

We would otherwise be left wondering why unacceptable justifications for an unreasonable policy stood unchallenged in a city known for its pragmatism.