Very true...however, some of our classical dances make you gain and lose weight disproportionately...But on the whole any vigorous dance is good for losing weight In fact many gyms and dance classes train you to learn movements that help you reduce weight .

Dance is an activity. That too a vigorous activity. Except for a few dance forms almost all the Dances are vigorous activities. This vigorous activity helps in not only weight reduction, but it helps in a plethora of health benefits like eradicating depression.

Of all the Dance forms Kathak involves fast and brisk movements. This in turn cures many ailments. Depression can be cured very effectively through Dances.

Why not, almost all the dances have the potential to help in losing weight. Additionally dance prevents obesity too.

as to loss weight we all should posses yoga because it is one of the kind of dacing only it has no different with dance

Yoga is not a dance. It's a collection of yoga Asanas and breathing techniques like Pranayama. But you can see some dance forms feature some Yoga Asanas. You can see some yogic features in Bharata Natyam. Because of these reasons Dances help in weight reduction.