Two windows and a section of the glass exterior of a commercial building fell in various parts of the city yesterday, bringing the number of such cases to about 40 in the past month. No one was injured in the three incidents yesterday, which occurred in Yau Ma Tei, Choi Wan Estate in eastern Kowloon and North Point. The first incident happened at 9am. A 1-square-metre piece of glass dropped from a commercial building in Yau Ma Tei onto a car, scratching its roof and boot. Officers said the glass came from the 22nd or 23rd floor of the building in Shanghai Street. Buildings Department engineers inspected the building and declared it safe. A spokesman said investigators would return to determine the cause of the accident. Workers from the building's management company were told to clean the exterior, check for cracks on any glass panels and remove any loose materials. At 1pm, meanwhile, a window fell from the 16th floor of a block of flats in Choi Wan Estate in eastern Kowloon, hitting the windscreen of a moving van. Police said the window fell after the resident of a flat in Yau Lung House had opened it. The man was arrested. At about the same time, a window fell from a flat on the 15th floor of a building on Wharf Road, North Point. A 53-year-old woman was taken to the police station to assist with investigations. The frequent incidents over the past month have highlighted the danger of loose and corroded aluminium window frames. The Housing Department has promised to spend $68 million to insert an extra screw in windows at 53 housing estates.