China has announced unprecedented measures to cut air pollution during this year's Olympic Games.
Air quality is a major concern for organisers of the Olympics
Starting this weekend, a new standard for car emissions will come into force in Beijing.
Some areas surrounding the capital have also joined in efforts to help reduce air pollution.
China has pledged Beijing's air quality will be up to the standard laid down by the World Health Organisation during the Games in August.
However, the air is still too dirty. One of the four indicators - the density of breathable particles in the air - is still too high.
To cut pollution, a new standard for car emissions will be enforced from 1 March, falling in line with the latest European Union standard.
A new type of less-polluting petrol will be available too.
Cars and buses that fail the checks will be banned from the streets.
More than 1,300 petrol stations in Beijing are being upgraded to cut fumes and the rest will be shut down.
In addition, the Chinese authorities have ordered five provinces around Beijing to join the efforts and reduce industrial activity for two months before the Games.
The measures cover the neighbouring city of Tianjin, Shandong province to the east, and the vast region of Inner Mongolia to the west.
From July both Beijing and Tianjin will restrict private car use, allowing only odd or even registration numbers to go out on any given day.
China hopes such drastic measures can reassure foreign delegations that there will be no heavy pollution to harm their athletes.