The monopoly of Chinese refineries has empowered them to raise fuel prices quickly and cut prices slowly, says an article in Chinese Business View. Excerpt:

Chinese people must be quite familiar with how fuel prices are raised. First, major State-owned refineries complain to the government fuel prices are far below the international level, for which they are incurring heavy losses. Second, some relevant government departments begin making noises, saying they can't see national assets being devalued, and asking the government to raise oil prices. Third, refineries announce a price rise. And last, some experts comfort the public with their weird logic that the price rise would have a "limited" impact on the economy, and there is still room for a new round of price increase.

But when global oil prices dropped to their lowest in recent times (below $40 a barrel in December), Sinopec and PetroChina didn't show even a fraction of that haste to cut prices. Some private gas stations cut prices out of their own volition, though, to attract consumers. Asked why it reacted so slowly when it came to lowering prices, Sinopec said that's because they hadn't got the directive from the National Development and Reform Commission.