The decline intensified during the day in line with developments in Asia and the rest of Europe.
The tangle around the Chinese real estate company Evergrande and its indebtedness has contributed to market turmoil, and the situation is tense ahead of interest rate announcements from the US, UK and Japan later this week.
The engineering and raw materials sector fell sharply.
The engineering company Atlas Copco was the heaviest on the OMXS30 list.
The company's A share fell 4.9 percent and the B share 4.6 percent.
Sandvik lost 4.0 percent while Boliden lost 2.9 percent.
The cloud service company Sinch closed 3.8 percent minus.
A few companies went against the flow, including Astra Zeneca, which raised 5.2 percent based on a news that the drug Enhertu prolongs survival for patients with breast cancer.
The leading European stock exchanges also had a dark day.
The Frankfurt Stock Exchange fell 2.3 percent, the London Stock Exchange fell 0.8 percent while the CAC40 index in Paris closed 1.7 percent minus.