Residents in north-east China are experiencing unannounced power cuts, as an electricity shortage which initially hit factories spreads to homes.
People living in Liaoning, Jilin and Heilongjiang provinces have complained on social media about the lack of heating, and lifts and traffic lights not working.
Local media said the cause was a rise in coal prices leading to short supply.
The country is highly dependent on coal for power.
One power company said it expected the power cuts to last until spring next year, and that unexpected outages would become "the new normal". Its post, however, was later deleted.
The energy shortage at first affected manufacturers across the country, many of whom have had to curb or stop production in recent weeks.
But over the weekend residents in some cities saw their power cut intermittently as well, with the hashtag "North-east electricity cuts" and other related phrases trending on Twitter-like social media platform Weibo.
The extent of the blackouts is not yet clear, but nearly 100 million people live in the three provinces.
In Liaoning province, a factory where ventilators suddenly stopped working had to send 23 staff to hospital with carbon monoxide poisoning.
There were also reports of some who were taken to hospital after they used stoves in poorly-ventilated rooms for heating, and people living in high-rise buildings who had to climb up and down dozens of flights of stairs as their lifts were not functioning.
One video circulating on Chinese media showed cars travelling on one side of a busy highway in Shenyang in complete darkness, as traffic lights and streetlights were switched off. City authorities told The Beijing News outlet that they were seeing a "massive" shortage of power.
Social media posts from the affected region said the situation was similar to living in neighbouring North Korea.
The Jilin provincial government said efforts were being made to source more coal from Inner Mongolia to address the coal shortage.
Power restrictions are already in place for factories in 10 other provinces, including manufacturing bases Shandong, Guangdong and Jiangsu.
China's leader Xi Jinping has pledged that his country will reach peak carbon emissions within nine years.
However, various regions have been criticised by the government for failing to make energy reduction targets, putting pressure on local officials not to expand power consumption, the BBC's Stephen McDonell reports from Beijing.