Chitta is the ego or “mind-field” and is like a white screen, which gets coloured by…

… MANAS (mind, mental functions, its the manifestation of the Trigunas)
… BUDDHI (intellect, discrimination power, is another word for “Chitta” in Samkhya Philosophy) 
… AHAMKAR (ego, feeling of “I”)

Chitta is the memory bank, which stores impressions and experiences, also from “Samskara” (past (life) experiences). Chitta is three-gunas-qualified and depending upon the domination of the chitta by these gunas there are five states of “Chitta Bhumis”. The theory of Chitta Bhumis originates from the Yoga Sutras and is elaborated upon by the sage Vyasa in his commentary of the Yoga Sutras. Chitta Bhumis (translated as Chitta `Platforms´) refer to the condition or a state of mind.

• MOODHA STATE (Tamasic) – laziness, dullness, lethargy, low self-esteem, …
• KSHIPTA STATE (Rajasic) – confused, hypersensitive, aggressiv, restless, …
• VIKSHIPTA STATE (Rajasic and Satvic) – curious, steadiness for developing, disciplined to reach a satin state, between opposites, …
• EKAGRA STATE (Satvic) – one-pointed, focused, concentrated, …
• NIRODHAHA (no Gunas) – no-mind-state, Moksha-state, restrained Chitta 

Chitta Vikshepas refer to distractions of the mind.
Yoga can be considered as concentration, therefore, Patanjali names nine obstacles for the mind-distractions:

1. Physical diseases (Vyadhi)
2. Mental lethargy (Styan)
3. Doubt (Samskaya)
4. Misplaced priorities (Pramada)
5. Physical laziness (Alasya)
6. Attachement/ lost control of sense objects (Avirati)
7. Delusion/ misunderstanding
8. Instability in regular practise 
9. Instability of mind/ knowledge 

These Chitta Vikshepas or nine obstacles are invariably accompanied by some symptoms:

• Dukha: pain, unhappiness
• Daurmanasya: despair, bad mind-state
• Angamejayatva: tremors in the body 
• Shvasaprashvas: erratic breathing pattern

Patanjali describes Chitta Prasadana or how to maintain a satvic Chitta/ mind-state for four different life situations or four different approaches towards four different types of people. Chitta Prasadana are recommended attitudes to keep the Gunas balanced in a satvic state: In happy moments or with happy people one should develop a friendly attitude (Maithri). For unhappy situations one should develop compassion and mercy (Karma). For virtues (Mudita), actions and people one must encourage and take joy as an attitude. For people exhibiting negative qualities or non-virtues situations on must be neutral and equanimous (Upeksha).

Chitta Vritti Nirodhaha

Chitta Vrittis are modifications of the mind or moods or mental responses to external stimuli.
The Sutras continue with:

With all those Vrittis, the intellect is working. Therefore, they generate suffering and Samskaras. The mental responses are modifications in the form of thought waves. The Ego identifies with these thought waves. This wrong identification of the Ego sense with the “I” is the cause of all miseries. The following Yoga Sutras give answer of how to stop or control the modifications of the mind:

As mentioned in Yoga Sutra 1.5 Vrittis are invariably accompanied by Kleshas. Kleshas are natural tendencies we are born with, they are what generate pain in our experiences and they are mental in nature. It is not our experience per se which are problematic. They become problematic only because of the presence of Kleshas. These Kleshas manifest in a human being in four degrees:

1. PRASUPTA – Dormant, from past life
2. TANU – Weak, enfeebled, present
3. VICCHINA – Oscillating
4. UDARA – Abundant

Patanjali prescribes the practise of Yoga and meditation to transfrom the Kleshas into a state of ‘Tanu’.
The five Kleshas are:

AVIDYA – IGNORANCE
`Vidya´means `real knowledge´that is knowledge that helps to reach self-realisation and overlies life-death-circle. `A- vidya´ means therefore, ignorance in the sense of absence of real knowledge or a leck of spiritual knowledge. It is the mother of all other kleshas. It describes for example the wrong believe that the self and the soul are the same. However, the soul which is eternal and a real spirit differ from the self which is not eternal.

ASMITA – EGO
`A-smita´is the opposite of oneness, its the thinking and feeling of an “I”

RAGA – Attachement
Raga is the attachment towards all that generates pleasure like affection, love, etc.

DVESHA – Aversion
Dvesha is aversion towards all that produces pain thus we hate, etc.

ABHINIVESHA – Fear of Death
If one can eliminate the first Klesha, ignorance, one can dissolve all the other afflictions. The ultimate goal of Patanjali’s Ashtanga Yoga is Kaivalya, a state of freedom from all miseries and a state of pure awareness.