If you’ve paid attention to news from the glass and window industry for the past year or so, you might have noticed an odd story that crops up every now and then — windows falling from high-rise buildings in Singapore. This year, that problem seems to be worsening.

In the first five months of 2017, 28 cases of windows falling have been reported in Singapore, according to a story in The New Paper. In all of 2016, 16 windows fell from buildings.

Because the nation-state in Southeast Asia is one of the most densely populated places in the world (7,987.52 per square kilometer, according to the CIA World Factbook), plummeting fenestration is an obvious safety hazard. Luckily, no one has been injured by falling windows this year, though seven people have been hurt by them since 2005.

“They don’t need a direct hit to injure because they shatter,” Lee Koon Peng told Singapore Home& Decor last June. “A window is sharp, heavy and made of glass.”

Singapore’s Building and Construction Authority says about 80 percent of the fallen windows are casement products in which the aluminum rivets holding the friction stays had corroded in the city’s humid, tropical climate. It rains in Singapore about 178 days per year, and the average annual relative humidity level is 84.2 percent, according to the country’s National Environment Agency.

In 2004, Singapore enacted a law ordering home owners to replace all aluminum rivets in casement windows with stainless steel rivets. There are severe legal penalties for not complying with the law.

Failure to replace the aluminum rivets can result in a penalty of up to $5,000, a jail term of up to six months, or both. If a window falls because it wasn’t properly maintained, home owners can be fined up to $10,000, jailed for up to a year, or both.

A total of 307 people have been fined since 2006, according to the Straits Times.