- Melati and Isabel Wijsen started campaigning against plastic bags in Bali when they were 10 and 12 years old.
- They have since delivered a TED Talk and presented to the United Nations in New York.
(CNN)"Welcome to Bali! Do you have any plastic bags to declare?"
If you've traveled to the lush Indonesian island of Bali recently, you might have received this peculiar greeting at the airport.
It would have come from Melati and Isabel Wijsen who have been campaigning for four years to get plastic bags banned from their island.
When they started out, they were just 10 and 12 years of age.
And now, they're about to succeed.
Indonesia's plastic problem
Indonesia is the second largest plastic polluter in the world after China -- its plastic waste accounts for a whopping 10 per cent of marine plastic pollution.
The Indonesian government has pledged to invest $1 billion in reducing marine waste by 70 per cent by 2025, as part of the UN's Clean Seas program.
The goal is ambitious, given the dire state of some of the country's 17,000 islands, including Bali, which has a population of just over four million.
Due to the massive amounts of trash in the waters, when the wet season arrives and the winds turn, beaches on Bali are hit by the annual "trash season."
The local government downplays the event, on one occasion calling it a "natural phenomenon," but at its root are poor disposal systems and a lack of education on the problem of waste.
Start with the bags
Growing up on Bali, Melati and Isabel were surrounded by the negative impact of plastic.
"There's no escaping it here," Melati tells CNN. "The plastic problem is so in your face, and we thought: 'Well, who's going to do something about it?'"
A fateful day at school gave them the motivation they were looking for.
"We had a lesson in class about positive world leaders, change makers like Nelson Mandela, Martin Luther King, Lady Diana, and I remember at the ages of 10 and 12 we went home thinking about what we could do