Disease, mental laziness, doubt, carelessness, laziness , non-abstention , false perception , failing to obtain stages of practice and inability to stay in that state - These distractions of the mind are the impediments.

Verse 30

व्याधि स्त्यान संशय प्रमादाअलस्याविरति भ्रान्तिदर्शनालब्धभूमिकत्वानवस्थितत्वानि चित्तविक्षेपाः ते अन्तरायाः ॥३०॥

vyādhi styāna saṁśaya pramāda-ālasya-avirati bhrāntidarśana-alabdha-bhūmikatva-anavasthitatvāni citta-vikṣepāḥ te antarāyāḥ ॥30॥

Disease, mental laziness, doubt, carelessness, laziness , non-abstention , false perception , failing to obtain stages of practice and inability to stay in that state - These distractions of the mind are the impediments.

These nine types of obstacles usually prevent the meditators from progressing on the path of Yoga. The souls who did not have strong previous birth sanskaras surely face it but they should not leave yoga fearing these problems. In fact, yoga should be practised continuously.

Maharshi has organized these obstacles in a chronological order which is quite scientific. In case the meditator is suffering from a disease then he cannot sit for yoga practice and he will be distracted due to unwellness of his heart. So, disease is called the first obstacle by the Maharshi. Therefore, good health is the foremost requirement to take the first step on the path of yoga.

So the first obstacle should always be focused upon in order to work hard to overcome other obstacles too. You will not be able to cross the other hurdles if you are unable to walk the path of yoga. 

You may reach your destination one day if you continue the journey, but those who have not even started their journey will be lost. Therefore, it is very important that we either overcome the first hurdle on the path of yoga or do not let it appear.

The remaining 8 obstacles are related to body, boastfulness, intellect, ignorance etc. These can be removed with internal effort, understanding, practice, detachment and wisdom.

But the yogic meditators will have to constantly remember that we have to work hard to stay away from the first obstacle/disease to yoga.

The other 8 obstacles will become mild due to the meditator’s efforts made for total physical health. Meaning thereby, if the efforts for physical health are made with full concentration, then the other 8 obstacles will also get removed.

Complete physical health also includes dietary habits, thoughts, day to day behavior, samskaras and habits.

PATANJALI YOGA SUTRAS