Justin's parents are white dairy farmers, living on fertile land a short drive from the township. The family still keeps guns and dogs to deter attackers eight years after apartheid ended.

Justin and Visumzi feature in a film called "The Children of Rio" which charts the lives of seven children born in 1992, the year of the first Earth Summit at Rio de Janeiro. The film shows the problems of the world's poor have changed little since then.

It will released on Sunday as world leaders wrangle over the text of a draft at the second Earth Summit in Johannesburg.

Italian filmmaker Bruno Sorrentino told a news conference in Johannesburg that the film hoped to make environmental and development issues more accessible to the public by illustrating them through the lives of children.

The two South Africans were chosen to track progress in peace and racial equality.

Chinese girl Kay Kay was born in the sprawling and polluted city of Guangzhou while Erdo comes from a family of nomadic cattle herders in Kenya's lawless north.

Rosamaria's home is in a crime-ridden shanty town in Rio, a few kilometres (miles) from the original summit venue. Panjarvanam lives in Tamil Nadu in southern India, while Hailey's father was a coal miner in northern England in 1992.

HEART-RENDING PLEAS

Most had a tough start to life. Rosamaria's father abandoned her family when she was born. Visumzi's father died of pneumonia while Panjarvanam's dad died from chemical poisoning contracted at a local fireworks factory.

In the film, the children voiced heart-rending pleas for change.

Visumzi says he would like running water - and for adults to stop raping children.

Panjarvanam would like to see running water, good roads, buses and covers on gutters. She wants to stay at school and become a doctor, an ambition her paralysed, bedridden grandfather supports.

But her mother, who works at the factory in which her husband was poisoned, wants Panjarvanam to leave school and join her there making fireworks with her brother.

Erdo walks for an hour to school each day and says he would like to see more food aid. His mother Esther recognises the importance of education and tries to feed her family by tending a small plot of maize.

Guangzhou is less polluted than it was a decade ago and the authorities have planted trees and shrubs in the city.

Both Kay Kay's parents work long hours to earn $400 a month - a good wage in China. Alone for much of the day, Kay Kay dreams of "pots of money" and a pair of high-heeled shoes.

At a Children's Earth Summit in Johannesburg, teenagers from around the world summed up the hopes of their generation in a appeal to governments and summit delegates.

"Rio was about talking. Johannesburg should be about walking... Let this not be another Rio de Janeiro. We are committed to sustainable development, all we need is for you to be."