Snow storms that have stranded millions of Chinese travellers are a "severe disaster" that will continue for several days, top leaders have warned.
Relief work was continuing to be a tough task, the Politburo said after a second emergency meeting on Sunday.
Troops are working to clear blocked roads and rail lines, allowing some stranded passengers to travel.
But more snow is expected and heavy fog has also hit central provinces, adding to transport woes.
On Monday, visibility was less than 100 metres (109 yards) in areas including Hunan and Hubei provinces, two of the areas worst hit by the snow, Xinhua news agency said.
Severe snow storms have been affecting the region since early January, paralysing transport networks and leading to shortages of power, food and water in some areas.
Millions of people, many of them migrant workers, have been unable to return home for the Lunar New Year holiday, which begins on 7 February.
Hundreds of thousands of passengers have spent days waiting at packed stations or trapped on blocked roads.
Residents of some central provinces, meanwhile, have been without power and water for days.
China's leaders have been working hard to convince people that they are tackling the situation and prevent frustration boiling over into unrest.
"We have to be clear minded that the inclement weather and severe disaster will continue to plague certain regions in the south," the Politburo said after Sunday's meeting, which was chaired by President Hu Jintao.
"Relief work will continue to face challenges, posing a tough task."
Dozens of people have died as a result of the weather. On Sunday four people died when a snow-covered roof collapsed in the city of Nanjing, Xinhua news agency said.
A woman was also killed in a stampede at Guangzhou station, which has seen the worst of the crowding.
About 1.3 million army troops and reservists have now been deployed to help the relief effort.
On Sunday, they cleared the blocked Hunan province section of the Beijing-Zhuhai highway.
Chen Erqun, a truck driver, had been stuck there for nine days.
"What I want most is to reach Guangdong and take a good bath and then go to sleep," he told Xinhua news agency.
Forecasters have warned of more snow over the next few days.
The extreme weather, now in its fourth week, has affected an estimated 100m people, and caused 54bn yuan (£3.8bn) of damage.
Officials have warned of future food shortages because of damaged winter crops.