Indian Ocean Tsunami: 15 years on, countries safer due to early warning system

15 years ago today, a powerful earthquake triggered a tsunami that swept across Indonesia, Sri Lanka, Thailand, and 10 other countries. Waves were as high as 17 metres. More than 230 thousand people were killed. People near coastlines stood almost no chance in the absence of an early warning system. But today, as Natasha Hussain reports, countries are much better prepared