World Environment Day was established in 1974 "to encourage worldwide awareness and action for the protection of our environment". Since it began, it has grown to become a global platform for public outreach that is widely celebrated in over 100 countries.

La Giornata delle persone, the people day

It is the day on which all people are invited to take care of the Earth, or to do something to be part of the change. The Earth is biodiversity, it is natural resources, it is water, food, air.

World Environment Day through the years

The theme for 2006 was 'Deserts and Desertification', and significantly the "host city" of WED was Algiers. The slogan chosen for World Environment Day 2007 was in English 'Melting ice – a Hot Topic'? The host city was Tromsø, in Norway. In 2008 the theme was 'Kick the Habit! Towards a Low Carbon Economy'. Host city: Wellington, New Zealand. In 2009 it was: 'Your Planet Needs You-UNite to Combat Climate Change'. The host country was Mexico, a signal of South America's growing role in the fight against climate change, including the participation of its vast forested lands in the carbon credit market. Mexico is also one of the main partners in the Unep "Billion Tree Campaign".

In 2010 the slogan was "many species, one planet, one future". The theme chosen was biodiversity, as it was the International Year of Biodiversity. The centre of activities was Rwanda. In 2011 – the International Year of Forests – Unep chose to dedicate the occasion to the theme of defending the planet's lungs. Forests cover 31 per cent of land area; primary forests account for 36 per cent of total forested areas worldwide. In 2012, in the city of Rio de Janeiro, the theme was particularly timely: "Green Economy: Does it include you?".

At a moment when all of Europe was gasping under the debt crisis, the intention was to engage the inhabitants of the planet to do their part in the transition to a more environmentally "friendly" economy. The challenge of World Environment Day 2012 was therefore to make every citizen feel involved in the need for a new green stimulus across all sectors, from agriculture to industry to commerce. "We must dispel the myth that there is a conflict between economic well-being and environmental health – UN Secretary-General Ban Ki-moon kept repeating – with smart policies and the right investments, countries can protect their environment, grow their economies, create decent jobs and accelerate social progress."

From 2013 to today

In 2013 the theme was the food ecological footprint, with the slogan "Think, Eat, Save". The UN, through its agencies, chose to highlight the fact that every year one third of all food produced in the world is thrown away, either through waste or through the steps between producer and consumer. These 1.3 billion tonnes of food, worth one trillion dollars, would be sufficient to feed the 870 million people who go hungry every day, as well as avoiding monumental CO2 emissions. 2014 was the year dedicated to the sea, with "raise your voice not the sea level!", to raise awareness of the dangers that island nations will have to face as a result of climate change. In 2015 WED went viral: hosted in Milan, with the theme "Seven billion people. One planet. Consume with care", it became the most popular hashtag on Twitter in more than 20 countries.

Year after year, "the goal of the UN Day for the environment is to give a human face to environmental issues – the UN Italy office wrote in a communiqué exemplary for its clarity and conciseness – ensuring that people become active agents of equitable and sustainable development; increasing awareness that communities are of fundamental importance to changing attitudes on environmental issues; promoting partnerships that will guarantee all nations and peoples a safe and prosperous future."