Thirty two people were killed in accidents related to thick fog in China as most parts of the country got enveloped by thick smog and foul air, prompting officials to declare the conditions as "poor" in many places and "hazardous" in some others.
Heavy smog and fog on Sunday made Beijing the most polluted of 47 cities monitored nationwide, state run China Daily quoted officials as saying.
By midday on Sunday, Beijing's air quality was rated as "poor" by the China National Environmental Monitoring Centre, while some other areas were in different districts declared "hazardous".
The smog and fog were so thick that visibility levels dropped not only in Beijing but in several others cities which started clearing up in the night following heavy rain.
The conditions made authorities to ask people to stay indoors to avoid breathing foul air outside.
Many people complained of heavy eye irritation and soar throats.
At least 32 people have been killed in traffic accidents over the past few days as heavy fog shrouded huge swathes of the country, the daily reported.
The US embassy in Beijing also qualified the air near its compound in Chaoyang district as "hazardous" in its own measurements made available on the popular micro-blogging site, Twitter.
Wang Xiaoming, senior weather bureau official, told China Radio International yesterday that fog had started to accumulate in Beijing since October 7 and had stayed in the city due to calm weather.
"The air quality then started to drop sharply after pollutants filtered into the fog. The city's air quality has been below the national standard (fairly good) for four days since Oct 7," he said.
The heavy pollution day could not have come at the worst time for China as the country just finished hosting the last of the UN climate change conference in the neighbouring Tianjin city, where energy hungry China doggedly resisted any attempts to impose binding emission cuts.
The levels of pollution in Beijing surprised Environment Minister, Jairam Ramesh who arrived here on Sunday to attend the Brazil, South Africa, India and China, (BASIC) group meeting being held at Tianjin city to finalise their stand for the next month's Cancun climate summit.
China, the world's biggest emitter with 23 per cent green house gases, followed US, 22 per cent, EU 13 per cent and India five per cent.
Ramesh defended India joining hands with China in the climate negotiation talks, despite vast difference in emission levels saying that the joint fight is to resist an international legal binding agreement that could put constraint on economic growth in these countries.