Scenes of heavy air pollution and smog across large parts of China, including Beijing, are not simply deeply unpleasant. They mean people, particularly the old, very young children and those with respiratory problems, will die. The scenes are particularly disturbing for someone of my age and nationality as they bring home memories of the UK national catastrophe in the Great London Smog of 1952 which killed 12,000 people.
Not accidentally, in 1952 the UK's stage of economic development, its GDP per capita, was approximately the same as China's today. Looking at the lessons of London's pollution catastrophe, and how subsequently the situation in both the city and the UK was improved, may contain some lessons of use for China.
The Great London Smog of December 1952 lasted for five days. Visibility was reduced at best to a few meters, and in some cases to just one meter.
I had then just started school and the only way to find the route was to walk alongside the fences and houses on the side of the road. It was impossible to see traffic. Listening for vehicles had to be used to cross roads safely. The smog carried a foul smell of sulphur and soot. The immediate cause of the smog pollution was coal, from power stations and private houses, combined with vehicle emissions.
The immediate short-term death toll from London's 1952 smog was counted at 4,000 to 6,000 - mainly very young children and those with respiratory problems. This was itself enough to count as a national catastrophe - in proportion to China's population it is equivalent to 80,000 dying.
But the serious effects of the smog aggravated existing medical conditions and not all deaths were recorded immediately. The final death toll is now estimated at 12,000 - almost a quarter of a million in proportion to China's population.
This disaster was the culmination of a UK industrialization path which had placed few limits on pollution - 1952 was close to the period of the maximum share of industry in the UK's economy and before a shift into services began.
Therefore, both in terms of income per head and industrial structure, the UK was close to the position of China today. For a century, London had been notorious for its polluting fogs.
So severe were the consequences of 1952's London catastrophe that for the first time serious measures were taken to control pollution. A special act regulating pollution in London became law in 1954, and in 1956 the UK-wide Clean Air Act was passed. These banned many smoke-emitting fuels, raised the minimum permissible heights of industrial chimneys, relocated power stations away from cities and so on.
Simultaneously, measures were taken to clean the Thames, which had no fish due to high toxin levels, was biologically "dead" and had been so polluted that a person falling into it was taken to hospital for inoculations as routine.
So severe were London's pollution problems that it cannot be claimed that there was instantaneous success. There was a serious further smog in 1962 - although with no death toll approaching 1952's. Gradually, London's century-old pall of pollution, that had literally blackened every building within it, was lifted. Breaking the back of the pollution problem took over a decade - after 1962 there were no repeat smogs on an equivalent scale.
The cumulative result of the measures was dramatic. Most importantly, there was never a repeat of 1952's huge loss of life. The physical appearance of London changed. Previously, it had been pointless to clean its great buildings as they simply became contaminated. Now they became clean. Fish returned to the Thames - angling is now institutionalized.
What are the conclusions? First, that the UK paid a great price for its industrialization, as has China. In both countries people were lifted out of poverty but at the cost of immense environmental damage. Second, in the UK it was possible to reverse the fundamental consequences of this over one to two decades.
But this correction did not take place spontaneously. It required determined government policy with public support.
Free markets and low investment levels will not solve pollution problems. Free markets allow pollution and, as non-polluting technologies are in general more expensive than polluting ones, low investment levels also worsen pollution. To overcome the UK's 1952 catastrophe, strict government regulation, and high levels of investment in non-polluting power stations and industries, was required.
Given that this corresponds to the only economic way to deal with such problems, China will have to follow the same path. Hopefully, given its far larger population, China will never have to face a disaster on an equivalent scale to London in 1952 before such a course is followed.
The author is a visiting professor at Antai College of Economics and Management of Shanghai Jiao Tong University. He can be found at @JohnRoss431 in Sina Weibo.
Vehicles at construction sites make a huge contribution to the air pollution in China, but quantitative statistics to measure it are still lacking. In the US, controls on exhaust emissions by road vehicles are very strong, and nowadays pollution caused by non-road vehicles, such as those on construction sites, has surpassed the amount released by vehicles on roads.
China is a colossal construction site at this current social stage. The pollution caused by non-road vehicles can only be greater than that in the US.
A good environment comes from good protection, not strict monitoring. If you don't like smog, what you should do is not release your anger online. From now on, please stop overusing your car. Please walk on your feet if the destination is not far.
People are only worried and angry when the air quality index looks terrible. On other days, it seems that pollution is far from them. They forget about it and go their own way. Strictly speaking, I'm afraid in Beijing, each year the number of days air quality meets the standards is less than 50. The government should make policies to further control motor vehicles and punish factories that do not carry out environmental protection measures.
Some survey results show that in China, people are largely dependent on the government to be responsible for environmental awareness. People are aware of the problems, but they believe that it's the responsibility of the government. The public hasn't changed much despite the massive debate over PM 2.5, and every-one is waiting for someone else to take responsibility. Facing environmental issues, no one can sidestep responsibility. Action is pivotal to environmental protection.
To those who are complaining of air pollution: How many hours do you drive your car every day, and for how many days do you turn on your air conditioner in summer? Do you live in a house with heating in winter? And are you really willing to buy environmentally friendly products at high prices?
On Weibo, there's a group of angry critics who are strong in words but weak in actions. They follow others in jeering at the pollution, and use their keyboard to guide society. It seems that their criticism exempts them from responsibility, and they look like innocent bystanders.
Are there any detailed reports to explain why air pollution has become so severe in Chinese cities? People can only provide their suggestions when they know the reasons. At the moment, everyone is complaining. But what has led to the pollution? And what can individuals do? It seems that few people care about these things.