Last week, the worst "oil crisis'' that China has ever experienced swept the Pearl River Delta and then spread to other regions. It is a crisis that is likely manufactured.

That is no solace to private car owners who, in recent years, have begun to enjoy the privileges and pleasures of driving their own vehicles. Also feeling the burn is the National Development and Reform Commission, which is responsible for setting retail prices for refined oil products.

Whatever, it is certainly convenient for the two state-owned oil giants, Sinopec and PetroChina, the duopoly that has a stranglehold on the retail market.

There are strong reasons to believe the two have deliberately halted supplies to create seeming chaos. By doing so, the duopoly could well be killing three birds with one stone.

First, they want to pressure the NDRC for an immediate increase in oil product prices, thus cutting their considerable losses on refinery production stemming from the rising price of imported crude. It probably wasn't an accident that one Sinopec official in Guangdong commented publicly last week that one measure to ease supply shortages would be for prices to rise.

Second, the energy companies want to eventually force the NDRC to completely free oil product pricing so that they can completely dominate the market.

China's bureaucratic system makes it possible for the two giants to dare to challenge the NDRC's authority because, administratively, Sinopec and PetroChina are under the supervision of the State-owned Assets Supervision and Administration Commission, not the NDRC. And, in the bureaucratic hierarchy, the duo are vice ministry or ministry-level units whose top executives are appointed by the State Council or cabinet. Given the rampant turf protection and regionalism on the mainland today, it is not uncommon for government units with competing interests to run into conflicts.

Moreover, as Sinopec and PetroChina have listed many of their business operations in overseas securities markets, they are increasingly able to cite ``shareholder interests'' as an excuse to defy government orders.

The duopoly's third goal is to take the opportunity to acquire the few petrol stations that they don't already run. In Guangdong province, for instance, fewer than 15 percent of the service stations are run by independents which, nonetheless, must rely on the duopoly for their supplies. Starved of fuel products, these minor stations cannot hang on for long.

China's commitment to its accession to the World Trade Organization means the mainland must open its retail market for refined oil products to foreign investors. In the bid to blunt the oncoming competition, the duopoly's strategy seems to be to grab the biggest market share possible before the wolf comes. They have been very aggressive in acquiring petrol stations over the past couple of years.

In any case, Pearl River Delta cities began to face oil shortages about a month ago. Drivers seeking fuel discovered that the independents, which couldn't get supplies from Sinopec or PetroChina, were running out first. The crisis climaxed early last week, when even many of the stations run by the duopoly began to run short.

Chaos began to visit the PRD cities, particularly last Tuesday when, in Guangzhou, drivers blindly circled the city in the vain hope of finding stations that still had supplies.

Drivers had to beg passing vehicles for spare fuel or call their friends to help push their empty cars home. Many taxi drivers stopped operating because refueling was too costly.

In Dongguan Tuesday, some drivers complained that they had to wait for eight hours in long queues to refuel, and profiteering began. In Huizhou, some stations closed, with their staff selling gasoline by the bottle at five times the official price.

Heavily pressured by the Guangdong provincial government, the oil giants promised to ship more oil products in to ease the crisis. But they added there was no guarantee of an ample supply, suggesting the shortages could recur. Then reports began to appear of other provinces facing similar shortages - so much so that popular Internet portals including sina.com, sohu.com and netease.com, jointly appealed to car drivers to ride bicycles at least one day a month.

However, it is absurd to say that China is really suffering an oil crisis. As demand grows, domestic oil production and oil imports have also steadily risen. The State Council's Development Research Center projects that crude demand will reach 318 million tonnes for the whole of this year, of which 135 million tonnes, or 42.5 percent, will be imported - 2 percentage points higher than the 40.5 percent of last year.

Government-controled pricing may force the duopoly's refining business into losses, but they should be well offset by their oil production. On the whole, both will still make huge profits in the first half of this year. And, given the privileges the two companies enjoy, they should be responsible to ensure supply stability on the retail market.

But what are they doing now? The market chaos in Guangdong last week reinforces the argument I made in this column on August 1 that it is essential for China to break the duopoly of Sinopec and PetroChina when it moves to liberalize oil pricing.