This year's commemorations were held under the theme "Think. Eat. Save".
Gauteng agriculture MEC Nandi Mayathula-Khoza urged young people to focus on environment-related careers, as there were numerous employment opportunities in the sector.
Environmental Affairs Minister Edna Molewa is expected to deliver a keynote address at the event.
According to her department, Molewa is scheduled to launch the R300-million "Groen Sebenza" project, spearheaded by the SA National Biodiversity Institute.
The project is aimed at developing skills and bridging the gap between education and job opportunities in the biodiversity sector, the environmental affairs department said in a statement.
Groen Sebenza involves the placement of 800 unemployed youth in jobs across the public, private sectors and non-governmental institutions in the biodiversity sector for a period of two and half years.
The young graduates and matriculants were placed with partner organisations to enable them to gain practical work experience.
World Environment Day is celebrated on June 5. This year's commemorations were held under the theme "Think. Eat. Save".
In South Africa, the celebrations are amplified as June is recognised as national environment month.
The day was established by the United Nations Generally Assembly in 1972 at the Stockholm conference on human environment. – Sapa