Don’t let the "red alerts," smog-shrouded buildings or blotted-out sun fool you: Beijing and China on the whole appear to be gaining real ground in the war on pollution.

In 2015, Beijing saw a 16 percent annual fall in the concentration of the most deadly type of air pollutant, according to an analysis by the Paulson Institute and Greenpeace of air quality data from the United States Embassy in Beijing. Though virtually all of those gains were registered during the summer and early fall, they still proved enough to make 2015 the cleanest year since the embassy began publishing data in 2008.

Courtesy of The Paulson Institute Beijing's average monthly concentrations of cancer-causing PM2.5 particulates in micrograms per cubic meter (note: not AQI levels) from 2008-2015. The data is from the United States Embassy pollution monitoring.

Beijing’s own environmental officials announced a more modest 6 percent improvement in air quality this year, a smaller margin that some analysts chalk up to Beijing’s overly optimistic portrayals of pollution levels in 2014. (The Beijing municipal environmental protection bureau couldn’t be reached for comment.)

Those improvements were also mirrored across broad swaths of eastern China, with a Greenpeace population-weighted analysis of Chinese data showing 15 percent annual decreases in cancer-causing PM2.5 particles. A separate analysis by Berkeley Earth found an 8 percent year-on-year decrease across much of the country during April-November 2015, though the group cautioned that it was too early to call it a definitive trend.

Taken together, these changes may mark the first tentative victories since Chinese leaders declared a “war on pollution” in 2014.

Jeffrey Kesler Beijing's Workers' Stadium on smoggy and clear days in 2014.

But even with those improvements, the air in Beijing and much of eastern China remained extremely toxic. Studies have linked air pollution to shrinking life expectancy and over a million deaths each year. Beijing’s average pollution levels in 2015 still put it well in the “unhealthy” range and far above international standards for acceptable air quality.

The decline in average levels also proved unable to prevent extreme pollution events -- “airpocalypses” -- that smothered the capital during November and December. Those haze events prompted Beijing authorities to issue their first-ever pollution “red alert” this year. Data from the United States Embassy in Beijing shows 2015 experiencing the worst November-December since measurements began in 2008.

2015's roller coaster quality -- the best summer and worst winter on record -- has prompted further questions over what led to soaring pollution levels in November and December. Anders Hove, associate director of research at the Paulson Institute, says that part of the blame can be placed on coal-fired winter heating. While crackdowns on polluting steel or cement factories may have accounted for blue skies during the summer, officials can’t simply close down facilities that provided heating to residential areas in China’s frigid north.

Lauri Myllyvirta, an air pollution expert with Greenpeace, pins the blame instead on particularly bad weather patterns.

Daily variation in Beijing pollution levels is heavily dependent on weather conditions. Low winds from the south carry in toxic air masses from China’s industrial rust belt, while high winds from the north can clear out putrid skies in a matter of hours. During this past November and December, Beijing saw double the number of days with smog-forming weather conditions -- stagnant air and high humidity -- compared with 2014, Myllyvirta says.

Analysts agree, however, that the improvements seen during the rest of the year were not the result of especially favorable weather conditions. Beijing experienced average weather for much of the year, and a preliminary review by Robert Rohde at Berkeley Earth found that variations in weather didn’t explain the broad gains across eastern China during the summer months.

Instead the source appears to be intense structural changes in China’s industrial rust belt, paired with strengthened enforcement of new air pollution regulations.

“It seems very clear that [the improved air quality] coincided quite perfectly with a fall in industrial coal consumption and improvements in emissions standards and enforcement for power plants and industry,” Greenpeace’s Myllyvirta told The WorldPost.

For decades the industrial rust belt that surrounds Beijing grew rapidly by churning out ever-increasing quantities of coal-intensive steel, cement and glass. But these industries have been devastated by slowing infrastructure investments and slumping manufacturing profits. Steel firms are losing billions of dollars as prices have fallen 73 percent over the past two years.

Kevin Frayer via Getty Images Smoke billows from smokestacks and a coal-fired generator at a steel factory on Nov. 19, 2015, in the industrial province of Hebei, China. Crackdowns on polluting steel or cement factories may have accounted for blue skies during the summer.

Those changes are proving very painful at the local level, but they’ve also contributed to a sudden turnaround in China’s demand for coal. 2014 saw China’s first annual decline in coal consumption since at least the year 2000, and 2015 appears to have continued that trend. That sudden turnaround has led some to speculate that Chinese coal consumption may have already peaked.

On top of the slump in industrial output, Chinese leaders appear to be pulling out the stops when it comes to reducing pollution levels. Since the first major airpocalypse in 2013, Chinese authorities have issued a raft of new laws on air pollution, set up real-time public monitoring stations throughout the country and given teeth to previously toothless environmental regulations.

In the past, pollution regulations looked good on paper but they had little traction on the ground -- environmental fines were capped at levels that made polluting profitable, and local officials knew economic growth trumped environmental protection when it came to securing promotions.

But analysts say that Chinese authorities have stepped up enforcement through increased fines, inspections and new mechanisms for holding officials responsible. The new Environmental Protection Law of 2015 allows local environmental protection bureaus to levy fines on a cumulative basis, leading to far higher penalties than under the previous caps.

Kevin Frayer via Getty Images A Chinese woman collects coal in a sorting area at a coal mine on Nov. 25, 2015, in Shanxi, China. Some have speculated that Chinese coal consumption may have already peaked.

In just the past week, China introduced a new air pollution law with strengthened penalties for polluters and increased rewards for whistleblowers, and also enacted a three-year ban on approvals for new coal mines.

The Paulson Institute’s Hove says Chinese authorities appear to be both issuing more specific regulations and taking a more comprehensive approach to limiting emissions.

“The government has not just done the typical shutting down of smaller and more inefficient facilities, but it’s also making plans for overall capacity in certain sectors,” Hove told The WorldPost.

Hove points out that Chinese authorities have also pledged to blacklist companies or individual officials that provide financing for actions that violate regional goals on coal reduction.

While 2015 contained many positive signs for trends in air pollution, questions abound for the years ahead.

Are declining pollution levels merely a result of economic weakness? If economic growth continues to slow, will Chinese leaders stimulate GDP by firing back up the steel furnaces? Will clearer summer skies give way to old-school pollution when the heating turns on? Will north China remain at the mercy of the wind for avoiding the airpocalypse?

Those are questions that will take years to answer.