The windows of the new Lantau cable cars should be screened to prevent smokers throwing cigarette ends into the shrubs below, a green group said yesterday. The call came as the MTR Corporation, which will operate the cable car service from Tung Chung to Ngong Ping on Lantau, prepares to test the cabins next month, ahead of a scheduled opening later this year. The 5.7km cable car route is part of the Ngong Ping 360 project, which also includes a new 'cultural village'. 'We had raised this [smoking] concern even when the system was at the design stage. But the ultimate design has made us worried. Even one cigarette end might lead to a hill fire in the ecologically important areas below,' said Alan Leung Sze-lun, a conservation officer with WWF Hong Kong. To maintain proper ventilation, all 112 cabins have windows at the top. But as there is no electricity in the cabins, smoke detectors could not be installed. Dr Leung suggested installing a screen to ensure items cannot be thrown out. Glenn Frommer, sustainability development manager of MTR Corp, said no-smoking signs and warning notices would be placed in the cabins and in the terminals. Dr Frommer said there would be special announcements on fire prevention in dry weather and signs reminding people not to smoke would be everywhere. At the mid-station in Nei Lak Shan where the cable car changes direction, a water tank would be available for handling small fires. Fire beaters would be available on the emergency trail along the cable car route. The trail, which is 1.5 metres wide to enable speedy evacuation, is already open for hiking. Meanwhile, the diversion of the Ngong Ping stream has been completed and river life has returned. But Dr Frommer said the stream had an excessive level of nutrients, a rich feeding source for algae growth, because toilet and kitchen sewage was being pumped continually into the water from village houses upstream. He said that improvements could only be made when all these dwellings were connected to the sewage treatment plant in Ngong Ping, which is expected to be completed in the first four months of this year.