KUALA LUMPUR, June 14 — A viral video of tourists taking a dip in the historic Sungai Melaka waterway has shocked and disgusted Malaysians on social media.

The 12-second video, which was uploaded on Twitter, showed two men believed to be foreigners jumping into the river, with another calmly enjoying his dip.

Most social media users who reacted to the video found the men’s actions ridiculous due to the river’s known high levels of pollution.

The video is believed to have been taken in January last year, but had only just made its rounds on social media.

The Melaka River had previously faced a severe pollution problem that caused its water to stink and turn black.

Earlier in May, hundreds of freshwater fish were found dead at Sungai Melaka waterway after a major pollution incident that was partly caused by the discharge of industrial waste.