Try to have a basic rock-paper-scissors template when it comes to anti-air against Chun.
If Chun is beating your air throw with an early jump attack, then you must anticipate this and use a Short Yoga Blast. Keep in mind, though, that sometimes you may have not read correctly and Chun did not jump. In situations like these it’s not uncommon for your opponent (if he or she is the type I have in mind) to jump immediately after seeing the whiffed YB. So perform another Short YB. You can keep doing the whiffed Short YB to discourage jumping so that eventually, she’ll block and try and slowly edge in. Have your ground tools at the ready.
If you are too far away for your close standing Strong to win, then you should walk/whiff Forward/Short slide within range so that the move can hit as desired.
If Chun is jumping from a close distance with anything but her jumping Short, you can whiff a Short slide and throw her from behind as she lands. Or, instead of throwing, you can use a Short slide x 2~3-> Fierce Yoga Flame or Yoga Fierce to push her out. Or, go on the offensive with Short slides, defensive crouching Strongs and Forward Drill Kicks etc.
When at a far distance, keep a note of how Chun is closing in on Dhalsim. If she is doing it by walking, then use the excellent far standing Strong and the somewhat decent far standing Short to keep her pinned down, with the occasional far standing Roundhouse mixed in to counter jumping. Use far crouching Fierce as a counter against her counters (standing Strong, crouching Strong, but not her crouching Roundhouse) to your far standing pokes.
And if she uses a crouching Roundhouse, wait for her to whiff and then use far standing Fierce to hit her in her recovery or just to inflict guard damage.
If she is advancing through jumping in, then she will eventually land shallow. Have a Forward Drill Kick ready for her as she lands, and go into a push-out sequence.
List of key anti-airs for Dhalsim:
- close standing Strong-> (if counter hit, cancel into Yoga Flame; Yoga Blast or Level 3 Yoga Strike)
- standing Jab-> Jab/Strong Yoga Fire; Fierce Yoga Flame; Short Yoga Blast. If it counter hits, this will be a 2-hit combo; if not, you’ll still be fairly safe.
- Short Yoga Blast. Learn to read your opponent so you can do the move in advance.
- Air throw. Shouldn’t really lose, even to early jump attacks, if you’re in the air before they are.
These are just the basic anti-airs, and are mainly for use at a close distance.
Additionally, try poking with far standing Strong when at a medium-to-far distance. It can often hit opponents as they start a jump. Far standing Roundhouse should be used over far standing Forward as it’s the better far anti-air move; familiarise yourself with its hit-area.