The Mahāmṛtyuñjaya mantra, (“Great Death-conquering Mantra”), is a verse of the Rigveda (RV 7.59.12). The verse also recurs in the Yajurveda (TS 1.8.6.i; VS 3.60). According to Shiva Puran when you have fear of any unknown event this chant helps you to overcome the fear.
Akal Mrityu is unnatural or untimely death. Accidents, suicides and homicides cause much suffering, pain and grief to the family. To avoid Akal mrityu for self and family, Mahāmṛtyuñjaya mantra can be used.
ॐ त्र्यम्बकं यजामहे सुगन्धिं पुष्टिवर्धनम्
उर्वारुकमिव बन्धनान्मृत्योर्मुक्षीय माऽमृतात्
Om tryambakaṃ yajāmahe sugandhiṃ puṣṭivardhanam
urvā rukamiva bandhanān mṛtyor mukṣīya mā’mṛtāt
OM. We worship and adore you, O three-eyed one, O Shiva. You are sweet gladness, the fragrance of life, who nourishes us, restores our health, and causes us to thrive. As, in due time, the stem of the cucumber weakens, and the gourd if freed from the vine, so free us from attachment and death, and do not withhold immortality
“This great Mantra in praise of Lord Shiva works wonders, averts accidents, heals diseases and grants long life. It will also liberate you from Samsara.” – Swami Sivananda