BEIJING, June 6 (Xinhua) -- These days, Beijing resident Xie Xiaoyang frequently shares photo collages of the city's blue skies on his WeChat Moments -- a stark contrast to the smoggy environment he remembers from his student days in the Chinese capital over 10 years ago.

"Social media was still in its infancy in China back then, with everyone eagerly sharing glimpses of their everyday routines," Xie recalled. "Yet as autumn leaves fell and winter set in, the world outside dissolved into a murky haze. Posting enthusiasm waned, giving way to a citywide yearning for crisp blue skies."

Over the past decades, air pollution has persisted as a major environmental challenge for China amid its rapid urbanization and economic development. In a landmark response, the Chinese government declared war against air pollution in 2013, launching its Air Pollution Prevention and Control Action Plan (APPCAP) -- a comprehensive national policy framework targeting air quality improvement -- and sought to find a better balance between economic growth and environment protection.

Following the introduction of the APPCAP, China became the first developing country in the world to impose large-scale efforts to reduce PM2.5 density, with Beijing taking the lead across Chinese cities by adopting scientific governance, institutional innovation and regional collaboration, contributing a new approach to global air pollution control. The United Nations Environment Programme has hailed the megacity's achievements in improving air quality as the "Beijing Miracle."

According to the Beijing Municipal Ecology and Environment Bureau, the capital reported steady progress in air quality in 2024. The average density of PM2.5, a key indicator of air pollution, during the year was 30.5 micrograms per cubic meter of air, down 6.2 percent year on year. The number of days with good air quality reached 290, an increase of 114 days compared with 2013 and the highest number on record. Notably, the number of heavily polluted days dropped from 58 in 2013 to just two in 2024, which was a reduction of 96.6 percent.

ARDUOUS CAMPAIGN

At this year's "two sessions," Minister of Ecology and Environment Huang Runqiu presented two filter membranes collected from Beijing's atmospheric environment monitors. The sample from 2015 exhibited a grayish-black hue, while last year's counterpart showed a grayish-white coloration.

"That grayish-black sample brings back memories of the days when my air purifier was working overtime," Xie said, voicing a collective memory shared by Beijing residents who lived through the city's smog-choked years.

"Beijing was then facing an acute air pollution crisis, making rigorous anti-smog measures an urgent imperative," said Li Xiang, an official of the local ecological environment protection's law enforcement authorities.

Building on the APPCAP, Beijing rolled out its clean air action plan from 2013 to 2017, launching a targeted campaign across four key battlefronts, including coal combustion control, vehicle emissions management, industrial pollution abatement and dust suppression.

"All relevant municipal authorities solemnly signed responsibility pledges, vowing to secure victory in this crucial pollution control campaign," said Xie Jinkai, director of the atmospheric environment department of the Beijing Municipal Ecology and Environment Bureau.

Beijing used to rely primarily on coal for winter heating. The first PM2.5 source analysis conducted in the capital -- spanning 2012 to 2013 -- identified coal combustion as one of the dominant contributors to local air pollution, said Wang Zifa, a researcher at the Institute of Atmospheric Physics under the Chinese Academy of Sciences.

The megacity therefore made a resolute decision to launch a wide-ranging initiative to switch from coal to electricity for winter heating. Wang Yu, a senior engineer at the ecological environment bureau of Beijing's Xicheng District who participated in the conversion project, recalled that the task was both complicated and arduous.

Environmental protection authorities and power supply companies conducted door-to-door surveys in target neighborhoods, addressing key challenges based on residents' actual conditions while carrying out various tasks, including upgrading external power supply facilities.

By the end of 2015, the downtown Xicheng District became Beijing's pioneer in achieving complete coal-free heating, a landmark transition that liberated residents from smoke-filled winters fueled by honeycomb briquettes. "Now our homes are warm and clean throughout winter. What a remarkable change," said a longtime resident surnamed Bai who lives in the Niujie neighborhood of Xicheng District.

Beijing also established a rigorous regulatory framework to accelerate coal reduction. The municipal government has successively implemented emissions standards for various facilities, including stationary gas turbines and boilers, setting stringent new limits on pollutants. Meanwhile, authorities have intensified their work against violations such as excessive emissions and abnormal operations of facilities. Key coal-consuming enterprises now face enhanced supervision to ensure compliance, with mandatory requirements for continuous green upgrades.

Through coordinated actions from authorities, industries and communities, the capital's plains achieved the fundamental status of being coal-free by the end of 2018, with coal-fired boilers virtually eliminated citywide.

According to Wang, Beijing's follow-up PM2.5 source studies revealed that coal combustion's contribution to PM2.5 dropped from 22.4 percent in 2013 to just 3 percent in 2017, eliminating its status as a major pollution source. And after five years of sustained efforts, Beijing saw its average annual density of PM2.5 decrease from nearly 90 micrograms per cubic meter to 58 micrograms per cubic meter, achieving its phased goal in curbing pollution.

PRECISION GOVERNANCE

In 2018, Beijing launched a "1 microgram initiative" to continuously improve air quality, shifting greater focus to sectors like vehicle emissions and fugitive dust, which demand refined control measures, and striving for even single microgram-per-cubic-meter improvements.

The year of 2021 marked a milestone in Beijing's decade-long "blue skies" campaign, with its annual average PM2.5 concentration dropping to 33 micrograms per cubic meter -- the lowest level since records began in 2013. The capital has since maintained compliant air quality standards for three consecutive years.

"'Beijing blue' has gradually become our new normal," Huang Runqiu said at a press conference.

Thanks to aggressive renewable energy adoption and coal-replacement policies, Beijing's energy mix has undergone a historic transformation. Its coal consumption plummeted from 21.8 million tonnes in 2012 to under 600,000 tonnes in 2024, now accounting for less than 1 percent of its total energy consumption, Yang Xiuling, director of the Beijing Municipal Development and Reform Commission, said recently.

Furthermore, Beijing has implemented structural optimization processes in its industrial and transport sectors. The city has closed over 3,000 manufacturing or polluting enterprises and rectified more than 12,000 scattered, disorganized or polluting businesses through categorized remediation. A total of over 3 million high-pollution vehicles have been phased out.

With its air quality having improved significantly, Beijing now faces more challenging pollution control targets that require increasingly scientific and refined measures. In 2025, the city elevated its air pollution governance to a new level of precision: its "0.1 microgram initiative."

"For instance, we will vigorously expand the adoption of new energy vehicles (NEVs), aiming for NEVs to comprise half of all registered vehicles by 2025," Xie Jinkai said. "Through meticulous governance, we aim to consolidate and sustain emissions reduction achievements."

According to the municipal government work report this year, the number of NEVs in the city has exceeded 1 million, and the proportion of green electricity in the city's energy mix has reached 26 percent.

MULTI-LEVEL COOPERATION

According to Li Xiang, an illegal sand and gravel plant in Dashiwo Town of Beijing's Fangshan District, which borders Zhuozhou City in Hebei Province, had once caused severe fugitive dust pollution in the local area.

"At that time, with Beijing and Hebei conducting separate law enforcement operations, the plant utilized vehicle-mounted mobile production equipment to shuttle across the provincial boundary, allowing the illegal operations to persist unchecked for an extended period," Li said.

Since 2015, the ecological and environmental law enforcement agencies of Beijing, Tianjin and Hebei have formally established and continuously improved a joint environmental enforcement mechanism, creating coordinated systems that involve regular consultations, joint operations and collaborative inspections to collectively combat cross-regional environmental violations.

After three years, the plant was officially shut down through a joint enforcement operation conducted by Beijing and Hebei authorities. In 2019, the Beijing-Tianjin-Hebei region expanded its joint law enforcement mechanism to cover district and county levels.

Beijing has broadened its air quality governance collaboration from a domestic level to an international level in recent years. Beyond hosting an annual international forum on clean air and climate to facilitate exchanges among environmental experts, policymakers and businesses globally, the city also took a significant step earlier this year, when the Beijing Municipal Ecology and Environment Bureau signed a memorandum of understanding with the Environment Department of the Bangkok Metropolitan Administration to boost air quality monitoring and management cooperation.

Over the next three years, Beijing will share its proven expertise in air pollution control -- particularly its PM2.5 monitoring and mitigation strategies -- with Bangkok to support the Thai capital's air quality improvement efforts.

However, Xie Jinkai noted that Beijing's current air quality improvements remain fragile, with regional pollution spikes likely to recur during unfavorable meteorological conditions.

"Air quality improvement remains a long-term, complex and challenging mission. Beijing's pollution control efforts will continue advancing to deeper, more precise stages," Xie said.

"Our shared goal is to maintain lasting blue skies and fresh air, continuously meeting the people's growing expectations for a beautiful environment," she added.