This [Mahābandha] certainly stops the upward movement of all the nāḍīs;this Mahābandha truly bestows great siddhis.

Sarva-nāḍīnām ūrdhvaṃ gati-nirodhakaḥ — stops the upward movement of all nāḍīs.Although the general objective of yoga is to raise prāṇa, here the meaning is different: the dispersion of prāṇa towards the extremities and the surface of the body is prevented.

Normally, the energy flows out through the thousands of nāḍīs.Mahābandha redirects all this flow towards the central channel.By closing the energetic “leaks”, the internal pressure increases and the prāṇa is concentrated.

Mahā-siddhi-pradāyakaḥ — bestower of great siddhis.Benefits include awakening of Kuṇḍalinī, insight into inner nāḍas, states of meditative absorption, and classical yogic powers.The name “maha” (great) indicates the supreme importance of this practice.