Beijing accelerates its fight against air pollution as it ticks to 100-day countdown of the 2022 Winter Olympics city-deciding vote.

Li Zhu (a pseudonym) and his colleagues stood in front of a distinctive chimney on Chang'an Avenue in downtown Beijing, waiting to take one last group picture.

Li was about to bid farewell to Guohua Beijing Thermal Plant, once a major pillar in Beijing's heating system. The plant, whose chimney soars 240 meters into the sky, was shuttered under a government plan recently.

"I have been working here for more than three decades, so it's hard to say goodbye," Li told the Beijing News.

Beijing has renewed its pollution-fighting efforts, including closing a series of coal power plants, to bring back "APEC Blue" -- a phrase coined by Chinese netizens to describe the city's clear skies during the Asia-Pacific Economic Cooperation (APEC) meetings in November.

The efforts are badly needed in Beijing, a city frequently enveloped in acrid smog, particularly as the capital and Zhangjiakou in neighboring Hebei Province pursue a joint bid for the 2022 Olympic Winter Games.

According to official figures, the plant's closure will help slash Beijing's coal usage by 1.3 million tonnes, or 14 percent of Beijing's total goal for the year, and cut emissions of sulfur dioxide, nitric oxide and dust by 1,410 tonnes, 2,690 tonnes and 420 tonnes respectively.

Guohua is not the only thermal plant to fade into history. Its shutdown came a day after the closure of another 93-year-old thermal power plant run by Beijing Energy Investment Group in western Beijing. Of the four major coal-fired power plants in Beijing, three have been closed so far and the last is scheduled to be closed next year.

Acrid smog has caused public discontent in Beijing, prompting local authorities to take actions to prevent it from worsening, including closing high-polluting companies, banning substandard vehicles and increasing funding to fight pollution.

In 2014, Beijing shut down 392 companies that cause pollution, upgraded 116 types of environmental protection equipment and slashed 2.3 million tonnes of coal use by closing the Gaojing Thermal Power Plant, one of the four major coal-fired plants.

Meanwhile, regional cooperation is high on the agenda for Beijing authorities in tackling foul air.

Wang Anshun, Beijing's mayor, said at the China Development Forum 2015 that Beijing will map out a long-term plan to combat smog and air pollution with neighboring Tianjin Municipality and Hebei Province last month. Tianjin and Hebei have also been shrouded in smog in recent years.

Regional cooperation to fight pollution has also won support from the central government. The National Development and Reform Commission issued a circular stating that the central government will allocate a total of 1.5 billion yuan (241.5 million U.S. dollars) in funds to help six localities, including Beijing, Tianjin and Heibei, treat air pollution.

For Li Zhu, it may be painful to say goodbye to the historic Guohua plant, but he said it is worth the loss as long as it benefits the environment.

The IOC has sent an evaluation team to China in March and will select the host city of the 2022 Winter Games from either Beijing or Almaty, Kazakhstan, on July 31 in Kuala Lumpur.