"We will build a green earth. This is our pledge on World Environment Day," West Bengal Chief MinisterMamata Banerjee tweeted.

The Indian Museum organised a workshop on clay modelling, painting, music, photography and origami with wildlife as its theme.

The British Council screened two documentaries - David Attenborough's 'Natural History Museum' and 'Wild Eye - From Himalaya to Bay of Bengal'.

NGO 'Nagrik' organised environment awareness programs at different places in the city.

The iconic Victoria Memorial was lit in green colours to mark the occasion.

To combat illegal trade in wildlife, the United Nations Environment Programme (UNEP) has kept the theme of "Go Wild for Life - Zero Tolerance for the Illegal Wildlife Trade" for this year.

"Today new demands in emerging economies are further driving the demand for illegal trade; if the demand is eliminated the poaching will stop. Awareness is crucial for reducing this demand and hence essential to associate the youth today in this mission," said Shekhar Kumar Niraj, country head of wildlife trade monitoring network TRAFFIC.