As athletes, officials and journalists descend on Beijing, one thing which is quickly getting their attention, is the thick layer of cloud which covers the city at present.

Here is how the sky looks today.

Beijing officials of course say the air quality has improved and it is only a problem with visibility.

“Today there is nothing critical preventing an athlete from running, except the visibility,” Dr. Patrick Schamasch, an orthopedic surgeon who is the IOC’s medical and scientific director said. “I can tell you it’s mist more than smog.”

I am not a meterologist, but fog in summer? I did a search in Google and found that San Francisco is well known to have “summer fog”. So is this fog or smog? Or a combination? Is it something people should be worried about?

The Beijing Municipal Environmental Protection Bureau said Sunday’s air was “unhealthy for sensitive groups.”

I think the only way for the sky to clear now, is to have a big thunderstorm. This is what the sky looked like one such day a few weeks ago.