Since it happened two days ago I wrote an article on why the exchanges do stop trading. As I did the research it was interesting to note that not all the exchanges in Asia have the same Circuit Breaker policy. Australia and Hong Kong for example never halt trading during a sell off. If you are interested to read my article you can find it here.
http://www.asiaetrading.com/articles/why_do_the_exchanges_halt_trading.php
http://www.asiaetrading.com/articles/why_do_the_exchanges_halt_trading.php
