Article published on the 2008-07-31 Latest update 2008-07-31 13:37 TU
These 200 have been added to an already-existing list of 100 of the city's biggest-polluting factories already on the list.
In addition, one million out of the 3.3 million cars on the roads have been banned since 20 July.
Olympic organisers have warned that events such as the marathon will be postponed or cancelled if the pollution rises to hazardous levels.
Environmental group Greenpeace has conducted an independent assessment of China's efforts to clean up the environment.
"The unsatisfactory air conditions we are seeing in Beijing is a result of many years of extensive economic development, neglecting the importance of environmental protection," Greenpeace China's campaign director Lo Pzeting told RFI.
While some measures taken surpassed the original guidelines, such as greatly improving sewage systems and partly using clean wind sources for electricity, China has increased its use of landfill and incineration to deal with waste.
On Thursday, China reiterated its determination to block internet access for reporters covering the Olympic games in August, despite international accusations of censorship.
Any site deemed sensitive by the Chinese government, including the Falungong spiritual movement web pages, will be blocked. This includes dissident organisations, Amnesty International and the Tibet government in exile.
The Chinese Foreign Ministry has been on the defensive this week after some US lawmakers dubbed the country's human rights record "odious".
"The US side has rudely interfered in China's internal affairs and sent a seriously wrong message to hostile anti-China forces," Foreign Ministry spokesman Liu Jianchao said on the ministry website.
Liu added that it was "unfair" that US Senator Sam Brownback claimed that visitors staying in foreign-owned hotels would be spied on by the Chinese government.
"In China, privacy is respected and guaranteed. In hotels and other places, there are no special measures that are beyond measures used internationally," said Liu.