A 23 years old boy, a badminton player, sustained injury of left ankle. He was immobilized for 3 months, the cast was removed and patient was able to walk normally. Later he complained of pain and swelling in the left calf, left ankle and foot. His mother massaged him for 30 minutes. After a while he developed acute onset of breathlessness and was brought to emergency and died. Most likely cause of death is:

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