If you usually have your nostrils congested in the morning and the water does not flow across both the nostrils in both directions because of this blockage, then it is better to practice jala neti after doing asanas.
If your nostrils are free flowing and you can do jala neti without any problem, then I would suggest you to do this cleansing action before practising yoga. This will help you to get more benefits as neat and clean nostrils will help you get good oxygen during practice when the blood flow to the desired organ / system. This will help the target organ / system get full benefit of that asana or pranayama.
RELATED:
- Checklist for Beginners to Jala Neti
- Dos & Donts during Jala Neti