Eerie photos spotlight Beijing and New Delhi's polluted air

On the same day the Paris climate summit got underway, Beijing suffered its worst air pollution of the year with monitoring sites throughout the city reporting extremely hazardous levels of pollutants, triggering a rare alert. It was a similar story in the Indian capital, too.

Chinese, Indian leaders in Paris for COP21 climate talks while their capitals choke in smog

Thomson Reuters · Posted: Nov 30, 2015 6:46 PM EST | Last Updated: December 1, 2015

Beijing and many cities in northern China recorded the worst smog of the year Monday, with air quality devices in some areas unable to read such high levels of pollutants. (Kevin Frayer/Getty)

This story is part of CBC News special coverage of climate change issues in connection with the United Nations climate change conference (COP21) being held in Paris from Nov. 30 to Dec. 11.

Beijing blanketed in worst smog of the year

While Chinese President Xi Jinping joined other world leaders in Paris for climate talks, schools in Beijing kept children indoors, highways closed and factories scaled back work because of thick, smelly smog that cut visibility to mere metres in the Chinese capital on Monday.

People in the Chinese capital complained of a smoky, pungent odour that led many to wear tight-fitting face masks like this one. (Kevin Frayer/Getty)

The last time Beijing issued an orange alert (the second-highest danger level on a four-tier scale) was in February 2014. (Jason Lee/Reuters)

The matter with atmospheric particulate matter

The concentration of hazardous particulate matter (known as PM2.5 particles) in the air exceeded 600 micrograms per cubic metre in places inside Beijing's urban centre, while readings as high as 976 micrograms were recorded at monitoring sites in some suburban areas.

The World Health Organization considers anything above 25 micrograms per cubic metre on a 24-hour average to be unsafe. (Kevin Frayer/Getty)

Red alert too disruptive

Critics inside the country say authorities held back from issuing a red alert because China's highest warning is too disruptive, requiring at least half of the vehicles on highways to be pulled off the road and the suspension of schools.

A baby peers out from inside a stranded vehicle on a highway between Beijing and Hebei, which also reported extremely polluted air Monday. The highway was closed due to smog. (Damir Sagolj/Reuters)

Thick smog didn't stop this man from getting out with his kite in Baoding on Monday. The northern city, located in Hebei province neighbouring Beijing, was the most polluted city in China in the first half of 2015, according to the country's Ministry of Environmental Protection. (Damir Sagolj/Reuters)

Winter is worst for air pollution

An early cold snap in November meant winter heating — much of which is generated by coal-fired plants and wood fires for many poorer residents — was contributing to a worsening of air quality, which deteriorated over the weekend.

Beijing has vowed to clean up its notoriously foul air and had been doing fairly well this year, with generally cleaner air than in 2014 — the last time Beijing issued an orange alert. (Kim Kyung-Hoon/Reuters)

While air quality plummeted in Beijing, representatives of the governments of more than 190 countries, including China, were meeting in Paris for the COP21 climate talks, which began Monday. (Lintao Zhang/Getty)

Winter is coming to New Delhi, too

Indian Prime Minister Narendra Modi left similar conditions in New Delhi as he departed for the Paris climate summit.

The Indian capital, which typically suffers a deterioration of air quality in the winter, was blanked in a particularly thick cloud of hazardous, choking smog on Monday.

High tension electric wires disappear into the haze on an extra-smoggy Monday in New Delhi. (Anindito Mukherjee/Reuters)

Too little, too late?

Initiatives to clean up Delhi's air have hit roadblocks in the past. A directive this year to ban all vehicles older than 15 years has been delayed and previous city governments have often ignored court orders to address pollution woes.