China has deployed a fleet of underwater drones called Sea Wing (Haiyi) glider in the Indian Ocean, which can operate for months and make observations for naval intelligence purposes, according to defence analyst HI Sutton.

Writing for the Forbes magazine, HI Sutton said that these sea gliders, which the Chinese are deploying “en masse”, are a type of Uncrewed Underwater Vehicle (UUV) which were launched in mid-December 2019 and recovered in February after making over 3,400 observations.

Citing the government sources, HI Sutton in his report said that these gliders are similar to those deployed by the US Navy, one of which was seized by Beijing in 2016 to ensure “safe navigation of passing ships.”

"Taken at face value, it may be surprising that China is now deploying these types of UUV en masse in the Indian Ocean. China has also deployed the Sea Wing from an ice breaker in the Arctic," HI Sutton wrote.

According to the defence expert, reports from December last year suggested that 14 would be employed in the Indian Ocean mission but only 12 were used. HI Sutton said that these gliders are unpowered with large wings to glide that can run for long periods of time, adding that they are not fast or agile, however, they are employed for long-range missions.

Furthermore, the defence analyst said these Chinese gliders that are placed in the Indian Ocean were reportedly gathering oceanography data, which "sounds innocuous" however, is commonly gathered for naval intelligence purposes."