Plumes of black smoke could be seen over large parts of central Stockholm after – fire and rescue services suspect – a biogas tube on top of the bus ran into a warning sign overhead and exploded, after the driver accidentally took a wrong turn down a tunnel at the busy Tegelbacken traffic junction.
No passengers were on the bus and the driver, who was taken to hospital with burn injuries, was described as being in a non life threatening and "serious but stable" condition late on Sunday.
Nobody else was injured.
IN PICTURES: Bus fire sends heavy smoke over central Stockholm
The tunnel, which is called Klaratunneln, reopened in a southbound direction on Sunday afternoon, but is expected to remain closed northbound for reparations until at least 4pm on Monday.
Bus commuters heading to Stockholm City Terminal are urged to seek alternative routes.
Public transport operator SL said the bus lines 809C, 812C, 813C, 815C and 818C linking Stockholm with its southern suburbs would only go as far as to Gullmarsplan.
From Gullmarsplan commuters can instead take the green metro line into central Stockholm.
SL also said that the lined 411C, 435C, 443C, 445C, 446C, 448C and 480C would not stop at the Stockholm City Terminal and urged commuters to instead travel via the bus station at Slussen.
For up-to-date information on travel times, check SL's travel app.
It is not known why the driver took a wrong turn, but it is not the first time it happens at the junction. A similar incident occurred in May 2013, but in that case the biogas tubes fell off but did not explode. Authorities suspect Sunday's fire was caused by the roof-mounted tubes colliding with a height warning sign.