The team from Cambridge Environmental Research Consultants, who were working on a project funded by the European Space Agency (ESA), turned their forecasts into a graphic map of the city, colour-coded by whether each district would pass official Chinese standards and updated daily.
At first it was freely accessible, but after earlier complaints by the Chinese authorities, it was restricted to users by password only. But on Friday, the day of the opening ceremony, the quarter of Beijing in which the Olympic Green is situated was coloured green on the map, marking an air pollution index (API) of 101-150. The government's safe limit is 100, and the city authorities' figures put the API at 95.
The reason for the "green" colour was high levels of particulates, known as PM10. Again, while the online map gave a fail for the Olympic Green, the figures for the nearest monitoring station in Beijing showed a pass.
Later on Friday afternoon, subscribers to the website received an email saying the site would no longer be visible by password. "I am very sorry to have to let you know that at the request of our Chinese partners in this project we are unable to provide public access to the Beijing Air Quality forecasts during the Olympic Games period," the email said.
EDIT
http://www.telegraph.co.uk/sport/othersports/olympics/2531259/Beijing-Olympics-British-smog-monitoring-unit-ordered-to-close-down.html