QIAOLI, China (NYTimes) - A monument to China's efforts to wean itself from coal rises on the outskirts of this village deep in the heart of the nation's coal country.

Scores of old coal stoves have been dumped in a lot, removed by government decree in recent months in favour of cleaner-burning natural gas furnaces.

"Defend blue sky and breathe together," an exhortation painted on the brick wall surrounding the lot says.

"Manage haze and work together." China has long faced scepticism over its pledges to wage a "war on pollution" and end its unrestrained burning of coal.

And indeed, demand for coal rose again last year after declining the previous three years.

This coal-stove graveyard, however, is a manifestation of China's ambitious effort this winter to all but end its dependence on coal for heating homes and businesses in hopes of clearing up the country's eye-watering, throat-scraping pollution.

The central government has set specific targets and backed up its decrees with threats of fines and other punishments.

What has happened here in the northern Chinese province of Shanxi, the country's largest coal-producing region, and in other regions shows how far the government has gone in imposing its environmentalism from above.

Eager to impress Beijing, officials in this province of 37 million people have moved so aggressively that in some cases they have created unintended consequences.

Many coal stoves were removed before new furnaces were installed, leaving tens of thousands of people shivering without heat when winter's first cold snap arrived earlier than normal.

Then, with so many districts switching to natural gas at once, demand for the new source of fuel overwhelmed supplies, sending prices soaring and creating shortages.

The benefits of the government's campaign are nonetheless being felt in the comparatively blue skies that have blessed Beijing and other cities that were a focus of officials' efforts, including in Shanxi's provincial capital, Taiyuan.

Longer term, the impact could be felt globally, too, backing up President Xi Jinping's pledge to put China in the "driving seat in international cooperation to respond to climate change" by reducing emissions at a time when the United States under President Donald Trump has treated the issue dismissively.

"It's definitely had a major impact on air quality already, and it's going to have a major impact on coal production in the future," said Lauri Myllyvirta, an energy analyst with Greenpeace in Beijing.

"There's a plan to carry out these policies over a much larger area," he said, adding that the accomplishments thus far "took a huge amount of determination".

Household and commercial users of coal represent only about six per cent of China's total, but they do not have the filtering systems of bigger coal users, mainly government power plants.

That means that reducing use of coal in homes and businesses has a disproportionately large effect in reducing coal-related emissions.

"The emissions are much, much higher, so conversely, the air pollution benefits are much greater," Peter Fraser, the head of the gas, coal and power markets division of the International Energy Agency in Paris, said in an interview.

China's plan - announced in March and intensified in August - demonstrated the power of centralized authority but also the bureaucratic shortcomings in Beijing's decrees.

Greenpeace mapped thousands of complaints about heating from social media posts. One photograph that circulated widely online before being censored showed a school in Hebei province, southwest of Beijing, holding classes outside in the sun because the heating was not working inside.

The outcry was such that the government took the unusual step of reversing a decree and easing the restrictions somewhat, allowing places with heating failures to resume using coal.

In Beijing, officials had to abandon, at least temporarily, a heavily promoted policy to end all municipal coal use, and restart a coal-fired power plant in the southeast suburbs. Hebei, the province that surrounds Beijing, has delayed a full transition from coal until 2020.

Huang Miaoru, who follows China for Wood Mackenzie, the energy consultancy, said that China's transition this winter was bedeviled by many factors.

Overzealous regional officials - eager to impress their national superiors, or afraid of disappointing them - had teamed up with private energy companies to convert more homes than supply could meet. (Nationally, natural gas demand surged 16 per cent in 2017, according to a report by the Rhodium Group, a New York-based consultancy.)

Despite the setbacks, neither she nor others said they expected the government to retreat from its goal to reduce coal use after decades in which industrialisation took precedence over the environment.

Last month, the Ministry of Environmental Protection announced plans to reduce pollution still further by 2020.

What is striking is the public support for the changes, which address nearly universal concerns in China about the impact of choking pollution on health and quality of life.

A ban on coal appears welcome even here in coal country.

The Coal Museum of China, in Taiyuan, celebrates the resource, declaring in an introductory film shown to visitors, "We should cherish this hard-won treasure." Even so, the province shut 27 coal mines last year. Taiyuan also banned the sale, transport or use of coal by individuals or small businesses.

In Qiaoli, a small village surrounded by orchards and fields, yellow pipes to carry natural gas now snake around old brick houses, fuelling heaters that the local government installed at no expense to the residents.

The village is on the outskirts of Linfen, an industrial city of 4.4 million that was once ranked among the world's most heavily polluted cities, a consequence of the unregulated boom of steel and other industries locating factories close to their fuel source.

Like much of northeastern China, even this region has enjoyed an unusual respite from the smog.

Li Lihu, a retiree who lives in a second-floor apartment in an enclosed courtyard, called the shift from coal a sign of China's progress. He said people in the area welcomed the relief from air pollution as much as, if not more than, residents in Beijing, where the smog was a national disgrace only a year ago.

According to Myllyvirta of Greenpeace, the pollution in Shanxi - as measured by the concentration of PM 2.5, or particulate matter of a size deemed especially harmful - dropped 20 percent in the last three months of 2017, after the start of the campaign to remove coal stoves, compared with the same period the year before. In Beijing, the drop was nearly 54 per cent for the same period.

To be sure, many Shanxi residents complained that the cost of heating their homes with gas furnaces or electric heaters was now much higher. Often they did so while wearing winter coats, hats and scarves indoors.

For some, the cost was prohibitively expensive. According to one shopkeeper, it now costs nearly as much to heat her place each month, about US$400, as the average monthly wage in the province, one of China's poorest, about US$650.

As a retiree, Li said he receives a subsidy from the local government.

"As long as the government keeps subsidising it, it will be OK," he said, carrying a plastic bag of chicken feet for his lunch. "If they stop next year, nobody will be able to use it to keep warm."

Coal is now effectively contraband in Qiaoli, though some residents continue to use it, claiming local authorities granted a reprieve until the Chinese New Year later this month.

"You're not going to report us, are you?" asked one villager who was unloading chunks of coal in the enclosed courtyard of his home.

His wife cheerfully showed how she still uses coal to feed the stove that warms the brick platform bed, or "kang," that is a traditional feature of homes in northern China.

Then he asked that he be identified only by his last name, Zhang, for fear of reprisals by officials for not using the newly installed gas heater instead. In at least two cases already, residents in the province were arrested after burning or selling coal, signalling officials' seriousness in enforcing the decrees here.

As for most things banned, a black market has materialised.

Zhang bought his coal behind a row of seemingly abandoned workshops outside of the village. A woman sweeping up coal dust in this makeshift market angrily shooed away three journalists who appeared, refusing to answer questions.

"The government is still very keen to clean up the energy market," said Huang, the analyst with Wood Mackenzie, "but we think because of the problems posed this winter, they'll take a more gradual approach in the future."