It took 22 people four hours and 30 grey bags worth of recyclable material to clean up a 150-metre stretch at the Natura 2000 site in Delimara known as Tal-Ballut. Two University-based student organisations, S-Cubed and Greenhouse, yesterday launched a series of clean-ups promoting a culture of active citizenship. The organising committee said it wanted to raise awareness of the natural environment by engaging students in hands-on initiatives.