I ask because the 2016 Summer Game (in Rio de Janeiro) will feature sailing events in some of the most polluted waters on earth. Supposedly, the waters of Guanabara Bay contain millions of tomes the safe levels of bacteria. My question: if a lot of people get very sick because of this, could the games be halted?
You assume the IOC cares about the health and safety of athletes or spectators.
That’s one for the record books! 
Munich and Atlanta were suspended, but it was decided ‘the games must go on’.
393-1896. 
1916, 1940, 1944 due to the World Wars.
The 1940 and 1944 Games were cancelled outright.
Moderator Note
Smapti, this being GQ, let’s avoid jabs like this, especially as the first response. No warning issued.
Colibri
General Questions Moderator
Right. I can’t see the games themselves being halted over such a relatively trivial issue (except for those who have to participate in the specific events). I would think that the first response would be to move the sailing and other aquatic events to another venue if one were available. If they weren’t, and a significant number of competitors became ill, I would expect only those events would be canceled, not the entire Olympics.
Here is a statement by the International Sailing Federation. Some steps are being taken to mitigate the problem before the games begin.
A bit nitpicky, but the most concerning tests – with levels over a million times above that considered acceptable at U.S. beaches – are for viruses, not bacteria. The bacteria levels were “only” 10 times acceptable levels. It’s especially concerning because the IOC has indicated they have no plans to include tests for viruses in their assessment of water quality.
In 1956, the Summer Games were in Melbourne Australia, but because of quarantine regulations, they held the equestrian events in Stockholm. So next year, they could move the sailing events to another location in or out of Brazil.
Not a full cancellation, but just last year in Sochi, the men’s snowboard cross event was changed due to fog. All of the seeding runs were cancelled. They still held the finals, but with a modified format.
Moved to the Game Room.
Colibri
General Questions Moderator
Did they make arrangements for Sydney?
Presumably the laws changed after many decades had passed.
I remember watching NBC’s olympic coverage, and hearing Jim Lampley explain that its wasn’t necessarily this time around due to “advances in veterinary medicine.”
In response to the OP’s question: they might possibly cancel the sports which are affected, though only as a last resort. (I think they would first look to move them to new location, even if it had to be in another country.) They definitely would not cancel the whole Olympics.
As long as the sailors aren’t swimming in it, I don’t see how they could get sick.
check that
Disgusting
If you look at the link I provided above you will see what their first resort is. They are making infrastructure improvements to help clean up the water.