Peking, smog.jpg
Photograph: EPA/ROLEX DELA PENA

The heaviest smog of the year blanketed the Chinese capital Friday on the eve of the country's annual parliament. 

The level of fine particulates hit the "hazardous" level of 452 micrograms per cubic metre overnight, according to the air quality index (AQI) by the US Embassy, and was at 405 micrograms at the time of writing. 

The maximum safe level is 25 micrograms, according to the World Health Organization. 

After relatively good air quality in January and February, the bad air returned just ahead the National People's Congress, which is expected to begin its yearly session on Saturday.

Beijing issued its first red smog alerts in December when the AQI hit 500, under a colour-coded system implemented in 2013.

The four-tier warning system has red as the most severe, followed by orange, yellow and blue. But last month, China made it harder to trigger a red alert. 

The highest alert will only be issued when the daily average AQI is forecast to exceed 500 for a day, 300 for two days in a row or 200 for four days, according to the official Xinhua news agency. 

The AQI on Thursday was over 300 on the index for the entire day.

Heavy smog is common in the winter months in northern China, where coal is widely used.  

Related stories

Heavy smog returns to Beijing

China smog shuts motorways, cancels flights

More than half of Chinese cities choking under smog

Beijing roads quiet as smog alert hits 24 Chinese cities

Record-breaking smog smothers northern China for fourth day

Latest news

Trump-style rhetoric is making world more dangerous, Amnesty says

Divisive and "poisonous" language used by politicians such as US President Donald Trump is putting vulnerable populations at risk and making the whole world a more dangerous place, Amnesty International charged on Wednesday.

Canada soon to begin resettling Iraqi refugees, most of them Yezidis

Canada will resettle 1,200 survivors of the Islamic State campaign to target religious minorities in northern Iraq, Canadian officials announced Tuesday. 

Breitbart editor resigns after release of paedophilia comments

Milo Yiannopoulos, a controversial editor at the far-right Breitbart news website, resigned Tuesday after the emergence of recordings in which he appears to defend sexual relationships between young boys and older men.

Trump administration opens door for mass deportations

The US Department of Homeland Security laid the groundwork Tuesday for mass deportations of immigrants living illegally in the United States under an executive order by President Donald Trump last month.

Brexit bill: House of Lords says public can change mind on leaving EU

The British public should be able to change their minds on Brexit - just as Prime Minister Theresa May did, the upper chamber of parliament heard Tuesday during a marathon debate on legislation to kick off EU negotiations.

Italian lawmakers, rights activists clash over gay sex club scandal

Gay rights activists and conservative politicians clashed Tuesday after the chief of Italy's anti-discrimination office quit over allegations that money had been authorized for gay sex clubs.

EU countries agree new rules to avoid tax evasion

European Union finance ministers in Brussels on Tuesday reached a political agreement on new rules to ensure that multinational corporations do not declare profits in the countries where they pay the least tax but in the countries where they generate it.

Trump condemns "horrible, painful" anti-Jewish incidents

US President Donald Trump condemned a recent spate of threats against Jewish community targets across the United States, during a visit Tuesday to the newly opened National Museum of African American History and Culture in Washington.

FinMin expects Croatia to exit Excessive Deficit Procedure this spring

Finance Minister Zdravko Maric said on Tuesday Croatia could exit the Excessive Deficit Procedure this spring and that it was showing progress in correcting macroeconomic imbalances.

Austria seeks to create jobs, but new EU immigrants need not apply

Austria plans to create 160,000 jobs in the next three years by subsidizing companies, but the project has raised concerns because it effectively excludes people who recently immigrated from other EU countries.

Juncker: Not good for W. Balkans that some in Washington want to water down EU

European Commission President Jean-Claude Juncker said on Tuesday it was not good for Western Balkan countries that some people in the new US administration gave the impression of being against the European Union because those countries needed the prospects of EU membership.

Citizens invited to help create Croatian version of Monopoly

A project to create a Croatian edition of Monopoly, in which citizens can participate by submitting proposals and which could become a souvenir for tourists, was presented at a press conference on Tuesday.

German state approves full-face veil ban

Legislation that bans face veils in select public spaces and situations was agreed by the government of the southeastern German state of Bavaria on Tuesday.

Indian restaurant Gaggan in Bangkok named Asia's best for third year

Bangkok's Indian eatery Gaggan on Tuesday was named the best restaurant in Asia for the third consecutive year by Asia's 50 Best Restaurants.

HGK: 16 Croatian companies to exhibit at IDEX defence exhibition

Sixteen Croatian companies will exhibit their products at the 13th IDEX 2017 defence exhibition in Abu Dhabi, to be held on February 19-23.