You're listening to the inquiry on the BBC World Service with me

Helen the Merriman. Each week we bring you four expert witnesses

answering one pressing question from the news. China 2016, the last day of the year.

Chau Fay wakes up hoping, just hoping, that today will be an extraordinary day.

He spent the last four years leading a campaign in China, one that many thought would fail, a campaign to ban ivory.

In his words, it was a last ditch attempt to save the elephant.

A hundred years ago, there were 10 million elephants spread across the world.

Now, there's under 500,000.

later that day, the announcement he's been waiting for comes. China, once the world's biggest ivory market, says it's to ban the domestic

ivory trade.

Chau Fay and his colleagues erupt and bring out the champagne.

We never thought this could happen, he says. videos circulate on social media, proclaiming 2017 the year of the elephant. Over the next few months, dozens of carving factories are shut down, and antique

cell assigned documents promising they'll no longer sell ivory. That was all a year ago. In January that band came into force.

May he has a lot of us. Chinese state TV has put out regular announcements,

warning people never to buy ivory again.

It's a remarkable turnaround for a country that was once in love with ivory.

Conservationists all over the world have praised China for doing something that not even Europe has.

And we want to know how it happened, how the seemingly impossible was made possible.

We're asking, how did China ban ivory? Van Ivory. Part 1, White Gold.

When I saw a small herd of elephant, five individuals, all females.

Our first expert individuals all females all females.

Our first expert witness, conservationist Chang Lee. He's never forgotten the first time he saw an elephant.

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