ENVIRONMENTAL groups are petitioning the United Nations to move the date of its green celebration because it is too close to the anniversary of the Tiananmen Square massacre. The UN launched World Environment Day on June 5 23 years ago. But since the 1989 crackdown local environmentalists have felt uncomfortable about celebrating it. 'We try to avoid organising anything on that day . . . people's minds are on other things,' said Alexander Wing Lok-yan of Green Power. 'Several green groups are going to approach the UN about this, but we doubt it will change.' It may also explain the low-key attitude many groups took. However, one environmentalist speculated the glut of 'Earth Days' and 'World Environment Days' was watering down their significance.