More than 20 primary school pupils hung yellow ribbons on a development site in Wong Tai Sin yesterday in a bid to prevent their school from being shrouded in a wall of concrete. Pupils at the Canossa Primary School at Chun Yan Street wrote their wishes on the ribbons they hung on the fence of their school's adjacent construction site, saying 'No buildings with wall-effect' and 'Care for nearby developments'. This came as Green Sense, which organised the petition, called for support for its proposal to tighten development limits for the site. The proposal, which demands the domestic plot ratio be reduced from 7.5 to 6.5 to 1 and non-domestic plot ratio from 1.5 to 1, is now open for a three-week public consultation on the website of the Town Planning Board. The group has also asked for the lot's building height to be capped at 25 metres, with 15 metres between blocks, and a setback of 5 metres from the primary school. Roy Lam Hoi-pong, the group's chairman, admitted there was only a slim chance of getting their application approved by the board but they would try to delay the land auction. 'The site is in the shape of a long strip and we believe it is highly likely the developments would be closely packed [together]. Even with a height limit of 140 metres, the buildings can still be 40 storeys.' This month Green Sense helped a Sham Shui Po resident take the government to court in a failed attempt to prevent a wall effect from development of a site in West Kowloon. The group has also filed another application asking the board to divide the former Valley Road housing estate site in Ho Man Tin into two lots to limit the size of the buildings. Meanwhile, Greenpeace has urged the public to join a power-saving campaign as the hot weather has pushed up energy consumption. The group said households should unplug electric appliances when not being used and adopt energy-efficient products while cooking.