Sarpa Dosha is recognised on the placement of Rahu in the birth Chart or Ketu or both. If it is because Rahu, who is identified with the energy of Durga and hence there is disturbance in the PINGALA Nadi. (Varahi is also the form Of Durga) We know Varahi is PINGALA NADI. She is also PITRU ROOPA according to Bhavanopanishad.
By performing rituals Sarpa Dosha caused by Rahu ( PINGALA NADI DISTURBANCE) is relieved.
Ketu represent the energy of both Ganapati & Subrahmanya and hence Subrahmanya is worshipped for getting relief from Sarpa Dosha, the disturbance in IDA Nadi, that is Chandra Nadi, also identified with Matangi (The intellect form of Sri Lalita Maha Tripura Sundari)
IDA is Chandra Nadi. PINGALA is Surya Nadi. The disturbance in these Nadis cause disharmony in Shatchakras because Rahu Kethu swallow Moon & Sun !!! ( belief system )
Rahu is Durga- Ketu is Ganapathi as well Subrahmanya.
Offering pooja to Rahu Ketu said to relieve from Sarpa Dosha.
That is all 6 chakras function properly by proper regulation of IDA, PINGALA NADIS
Sarpa Dosha & Pitrudosha many times go together because:
1. Varahi Pitru Roopa ( disturbance in Pingala)
2. Disturbance in IDA PINGALA Nadis is because of the genetic factors.
Hope by now, we have understood Sarpa Dosha, Pitru Dosha which is linked to IDA,Pingala and Shatchakras
Sarpa Dosha is said to have effect on one’s professional prosperity, growth and also in getting progeny.