China's economy may be the second largest in the world. But the Chinese economy, as financial markets see it, can still change direction with dizzying speed.

A few weeks ago, many commentators seemed to believe that the People's Bank of China, the country's central bank, was reacting too slowly to signs of the economy overheating. Now, after a run of weaker-than-expected data, many are worried that the pace of growth is already in rapid decline.

Certainly, there has been a shift since the start of the year. The push that the government's stimulus package gave to industry has subsided. Similarly, as incentives for consumers began to be withdrawn at the end of last year, the momentum of household spending started to slide. On one closely-watched measure, household spending is now growing at the slowest rate in nearly seven years.