A pink bag containing an urn with cremated remains left by a widow on a Shanghai Metro train was later returned to her. Photo: Screenshot from video by Wevideo

A pink plastic bag containing cremated human remains was returned to a grieving widow after she inadvertently left her "husband" under her seat on Shanghai's subway.

The widow, surnamed Wang, placed the bag with the urn containing her husband's remains under her seat on the city's line 8, according to surveillance video posted by WeVideo on social media on Friday. 

The video shows Wang arriving at her station and collecting her other belongings under arm, but leaving behind the pink bag under her seat. 

Realizing what she had done, Wang reported the loss to police who then searched through surveillance video that shows the bag tipping over and revealing itself on the floor several stops later. 

Finally, another passenger picks up the bag and reaches inside but does not seem to realize it is an urn containing human remains. 

The video shows the passenger leaving the train with the bag and walking across the platform among hundreds of other passengers.  

WeVideo didn't report how the cremated remains were actually recovered and returned to the widow.

"How could that woman forget her beloved one's ashes?" wrote a netizen. " I would be so sad if I were her husband."