What can cities do instead?
What you can do instead of killing them is sterilize the dogs. In India, where euthanasia is illegal, there was a huge program for this, and it reduced the stray dog population by 40 percent in three years. So it's possible to reduce the numbers. At the Commonwealth Games in Delhi [in 2010], there was a big sterilization project too, rather than rounding up dogs, because euthanasia is illegal there. But there were still problems -- they didn't do it as well as they could've done.
There were other problems too -- in Seoul, Korea [for the 1988 Summer Olympics], dog meat was a problem. In Beijing, they restricted dog ownership in the city to reduce the number of dogs. And I don't know what will happen next in Rio, or for the World Cup there.
It's an ongoing and continuing problem.
Why do cities with big sporting events cull their stray dogs?
Whenever there is some big event, people want to clean up the city. It's like when a guest comes over, you want to clean up the house. Well, lots of guests are coming in for big event, want to clean up the streets.