Besides being fairer, setting income tax thresholds also needs to be more resilient. Different thresholds should be used when the prices of necessities are different.

Far more feasible than frequently debating on whether and how to adjust the fixed threshold is to develop a threshold calculation pattern, allowing the threshold to be linked to other factors such as inflation.

What must be noted is that the threshold that has attracted the attention of most people is applicable only to income from salaries, which is only one among the 11 forms of tax laid out in the law. Many other items, though seldom noticed, make a much greater contribution to income disparity.

A typical example is tax on income from transfer of property, which includes the profit from buying and selling houses. Though its rate is as high as 20 percent, housing investors can easily evade the tax because their profit is hardly verifiable. So someone with a salary of 6,000 yuan might pay higher income tax than his colleague whose salary on paper is 3,000 yuan but whose profit from housing investments is 3 million yuan.

Even more embarrassing is a true story told to me by taxation officials from a coal-rich region. A miner who risks his life to make a living has to pay income tax, because his income is easy to confirm, while his boss can easily evade it, simply because his income is much less transparent.

How much tax you pay is dependent not on how high your total income is, but on how transparent it is, running counter to the basic aim of the tax. Instead of focusing only on the threshold for just one tax item, more courage is needed to deal with the core of the matter.

The journey to a fairer personal income tax system is long and arduous, but it has to begin now. What cannot be delayed is the creation of a system that effectively increases the transparency of the high-income group, and one that generates tax revenues from people's total income rather than one or two types of income.

In the long run, the individual income tax needs to be replaced by a household income tax, as most countries and regions have done. Only then can the tax truly match taxpayers' ability to pay.