Skanda Purana — Kashi Khanda, Shloka 84
दृढासनो यथाशक्ति प्राणं चंद्रेण पूरयेत् । रेचयेदथ सूर्येण प्राणायामोयमुच्यते
dṛḍhāsano yathāśakti prāṇaṃ caṃdreṇa pūrayet | recayedatha sūryeṇa prāṇāyāmoyamucyate
当以稳固坐姿，随己之力，由“月”之脉道吸满 prāṇa；继而由“日”之脉道呼出。此即名为 prāṇāyāma（调息）。
Skanda (deduced: Kāśīkhaṇḍa commonly Skanda → Agastya)
Tirtha: Kāśī
Type: kshetra
Scene: A yogin seated immovably; left nostril shown with cool moonlight stream entering, right nostril with warm sunlight stream leaving; subtle moon and sun emblems near shoulders.
FAQs
Breath-discipline is dharmic when done steadily, within capacity, and with balance of lunar and solar currents.
Kāśī is the sacred frame of the teaching; the verse itself is a practical yogic definition rather than a site-description.
Inhale through the ‘moon’ channel and exhale through the ‘sun’ channel while seated firmly—this is prescribed as prāṇāyāma.