A 52-year-old woman runner who took part in the Hong Kong marathon died Monday, a day after collapsing on the finish line of the 10-kilometre race.
The amateur athlete had been in a critical condition after the event Sunday, which saw 74,000 competitors pound the streets.
Hospital authorities said Monday the woman had died after she became unconscious and was taken into intensive care, but gave no further details.
She had participated in the race with her husband, who accompanied her to hospital, local television reported.
Sunday's marathon took place under blue skies but pollution levels were deemed "unhealthy for sensitive groups" with the Air Quality Index at 126.
Of the runners who took part, 11 were taken to hospital on Sunday, including the woman who died.
Authorities Monday said six people were still in hospital and all were stable.
Ethiopia's Bizuneh Melaku Belachew smashed his personal best to win the main 42km race in a new course record of two hours, 10 minutes and 31 seconds.