What is pulmonary thromboembolism that caused Prateek Yadav's death?

Massive pulmonary thromboembolism, which led to cardiorespiratory collapse and death of Mulayam Yadav's younger son Prateek, occurs when extremely large blood clot blocks one or more pulmonary arteries in the lungs. This can rapidly disrupt blood circulation and oxygen supply throughout the body. It results in cardiorespiratory collapse, which is sudden failure of heart/lungs to function properly.