Smog-smothered residents of China's capital city have started referring to the current record-high pollution levels in Beijing as the "air-pocalypse."

Pollution levels have hit record highs over Beijing in recent days, forcing schoolchildren and the elderly to stay indoors, clogging hospitals with respiratory cases and triggering a spike in demand for masks, with many stores reporting they are sold out.

"It's officially the worst air quality on record and in China's notoriously polluted capital that's saying a lot," said CTV's Beijing Bureau Chief Janis Mackey Frayer. "Heavy smog has choked Beijing for days, so much it's now being referred to as the 'air-pocalypse.'"

Early last year, the Chinese government began tracking and releasing the results of PM2.5 particle testing. The system measures the amount of particles in the air that are less than 2.5 micrograms in diameter -- those which have the ability to penetrate most deeply into one's lungs.

"Pollution levels on the weekend went off the charts, passing 700 according to officials on an index that maxes out at 500. Data from the U.S. embassy hit 886. The World Health Organization says a level higher than 25 is a risk," Mackey Frayer said.

The smog level peaked Saturday with off-the-charts levels that obscured Beijing's skyline in a thick grey haze that was expected to last through Tuesday.

By Monday, levels in Beijing had declined to around 350 micrograms -- but were still far higher than the World Health Organization's recommended maximum level of 25.

To provide context, Mackey Frayer said the average PM2.5 level in the city of Montreal is 11.

"The city's government has ordered factories, construction sites and cars to cut emissions. The smog could still linger for days so people are being warned to stay indoors and hope for a strong wind to bring relief," Mackey Frayer said.

The high levels of smog come at a time of increased transparency by China's government concerning public disclosure of pollution levels. The new stance was partially prompted by a Twitter feed from the U.S. Embassy that now sends out hourly PM2.5 readings taken by instruments situated on the roof of the embassy, as well as mounting demands from China's middle class for more clarity on the subject.

As a result, the Chinese government began issuing its own online air quality updates early last year for cities throughout the country.

Government officials held news conferences and posted messages on micro blogs discussing the pollution over the weekend and on Monday -- a significant change in tone from the past, when high smog reports were typically dismissed by officials.

"I think there's been a very big change," prominent Beijing environmental campaigner Ma Jun told The Associated Press, adding that the government knows it no longer has a monopoly on information about the environment.

"Given the public's ability to spread this information, especially on social media, the government itself has to make adjustments."

While the new level of openness has been welcomed by many Chinese, it has also added a level of pressure to the government to do something about the smog that often blankets the major cities, particularly the capital.

The government has been under pressure to investigate and address the underlying causes of smog -- among them, an apparent hesitancy to introduce Western-style emissions restrictions on vehicles, and to enact and enforce environmental controls for industry.

Mackey Frayer said Beijing's pollution problems are a product of the massive industrial change the country has experienced in recent years, its reliance on coal power, massive growth in the number of people who own cars, and the simple fact the city is hemmed in by hills which tend to trap the smog over the city.