This week's Audit Commission report on the effectiveness of the Hong Kong government's pollution policy makes depressing reading.
That is not so much because of the government's repeated failure to meet even its own modest environmental targets, although that's dismal enough.
No, the real reason the report is so discouraging is the sheer wilful official stupidity that lies behind the government's failure.
Back in the late 1980s, the government introduced targets for the maximum permissible concentrations of harmful atmospheric pollutants and set up the Environmental Protection Department to enforce them.
A quarter of a century later those targets look feeble compared with the latest international standards.
For example, the World Health Organisation's air quality guidelines recommend an annual average PM10 - that's cancer-causing diesel soot to you and me - concentration of no more than 20 microgrammes per cubic metre.
The Hong Kong government's target is not even half as onerous; a generous 55 microgrammes per cubic metre.
But the government has never come close to meeting even its own undemanding objectives. For instance, last year the average roadside concentration of lung-shrivelling nitrogen dioxide was 50 per cent above the government's target, and three times the WHO's ceiling.
Officials cannot blame their failure on pollution from the mainland. Yes, smog drifts down from Guangdong. But pollution concentrations are inversely proportional to the cube of the distance from the source.
So although a factory 80 kilometres away in Dongguan might emit 100,000 times as many pollutants as that bus roaring past you in the street, the bus is doing twice as much damage to your health. In short, the harmful stuff is pumped out right here in Hong Kong.
Yet the government has consistently failed to tackle the problem. Despite 10 years of official promises to clear the air, there are still more than 50,000 trucks and buses with highly polluting pre-2001 diesel engines plying our roads.
Similarly, the government has failed to introduce new standards requiring shipping to use less polluting low-sulphur fuels.
Meanwhile, most of the electricity we consume is still generated locally by burning coal instead of natural gas, which is much cleaner.
Nor can officials blame their failure to do anything on a lack of resources.
At the last count the Hong Kong government was sitting on accumulated excess reserves of HK$1.3 trillion. That's more than three years' worth of government spending.
And this is where we encounter mind-boggling levels of stupidity. Asked what all this money is for, officials occasionally mutter something about needing the reserves to meet future health care liabilities as the city's population ages.
Yet the single most effective thing the government could do to ensure it can meet its future health care liabilities would be to cut local pollution levels.
According to estimates compiled by the University of Hong Kong's School of Public Health, last year the city's high pollution levels were responsible for 8.7 million visits to the doctor, 24,500 hospital admissions and 3,600 deaths.
HKU estimates the total cost to Hong Kong's economy was more than HK$42 billion.
What the cumulative health effects of living in such a polluted environment will turn out to be over the coming decades is incalculable. But it is safe to assume that the annual cost will be many multiples of last year's figure, placing a massive strain on the city's economy.
As a result, on the principle that prevention is better than cure - and far better than palliative care - the government should do now what it ought to have done 10 years ago and spend as much as it takes to cut local pollution levels to meet, and even exceed, the WHO's most stringent guidelines.
In the short term, it should order all pre-2001 dirty diesel-engined vehicles off our roads. It should require all shipping to comply with the latest International Maritime Organisation emission standards, while insisting local vessels like ferries use only ultra-low-sulphur fuels. And it should compel Hong Kong's power companies to stop burning coal entirely, switching to natural gas as soon as possible.
In the longer term the government should draw up plans to phase out diesel-engined trucks and buses altogether.
Starting with the city's buses, it should replace them with electric-powered vehicles, moving the source of pollution away from street level where it does the most harm.
All this will be expensive. But Hong Kong can easily afford it. And in the long run the costs of doing nothing will be far higher.
Surely our officials aren't that stupid.