Manusmriti
उष्ट्रयानं समारुह्य खरयानं तु कामतः । स्नात्वा तु विप्रो दिग्वासाः प्राणायामेन शुध्यति ॥ २०१ ॥
A Brahmana who voluntarily rode in a carriage drawn by camels or by asses, and he who bathed naked, become pure by suppressing his breath (Pranayama).
english translation
uSTrayAnaM samAruhya kharayAnaM tu kAmataH । snAtvA tu vipro digvAsAH prANAyAmena zudhyati ॥ 201 ॥
hk transliteration by Sanscript