BRUSSELS -- The biggest annual conference on European environment policy, known as "Green Week," kicked off here on Tuesday to seek solutions to air pollution across the European Union.

Under the theme of "Cleaner air for all", the three-day conference from Tuesday brought together about 3,000 participants from non-governmental organizations as well as national and European institutions to discuss air-related issues. In addition, large-scale exhibitions were to showcase best environment-friendly practices, alternative fuel vehicles and test drives of electric cars.

"Air pollution is often invisible, but its effects are very real... Green Week provides an important platform where policymakers, representatives from local communities and NGOs, public authorities and businesses can exchange ideas on how to improve the air we breathe," environment commissioner Janez Potocnik said.

In the EU's most densely populated areas, there are substantial pollutants such as particular matter, ground-level ozone and nitrogen dioxide.

The European Commission is set to review its current air policy this year in the hope of finding ways to improve air quality across the EU.