There are a number of lasers that we currently use for the treatment of hyperpigmentation, or dark spots. Certainly, the Nd:YAG is one of them. Although it is not for everyone, it does work for a large majority of our patients. In the instance where the Nd:YAG is not successful in removing hyperpigmentation, I would consider two other lasers and one additional peel.
One of the other lasers is called the erbium laser, and the second is called the fractionated or CO2 laser. Both of these lasers have the potential of moving a little bit deeper into skin to eradicate unwanted hyperpigmentation.
In addition to these two other lasers, you may also want to consider other various peels. I understand, from your question, that you have tried the retinoid and glycolic peel; you might consider doing a stronger trichloroacetic acid peel. This particular peel should be used in caution for skin of color (given your Indian descent). However, a lower 20% trichloroacetic acid peel would also be a viable option. With these modalities, you may notice more successful hyperpigmentation removal.