Yoga or union (yuj = to yoke) of the individual self with the Supreme Self can be attained through yoga or perfect concen-tration (yuj = to get samādhi or superconscious state). All attempts at controlling the vagaries of the mind—which is constantly rising in the form of vṛttis or wave-like modifications—are foiled by antarāyas or ‘intruders’ which are actually obstacles in the path of yoga.
Patañjali lists them as nine in number (Yogasūtras 1.30):
There is a second set of such antarāyas (ibid. 1.31) which ‘coexist with mental distractions’ and are hence called ‘vikṣepa-sahabhuvaḥ.’ They are five:
All these disturb the mind and hence prove to be obstacles to the attainment of yoga.
For details, see under each title separately.