abolition of the caste system in india is a pressing matter, that in my opinion should be addressed under current conditions, it is an issue that cannot wait. but anyone can see the ruling classes, indian and foreign, aren't too concerned about the issue. the survival of this feudal system of social relation is an extraordinary example of india's position as a colonnial and since independence as a neo-colonnial state. abolition of such feudal remnants are directly in accord with the communist and anti-imperialist struggle.
that being said, in my opinion the third world faces many different and more difficult tasks than the first world. i don't think the affluent western countries have any social movements comparable to this kind of anti-caste movement, nothing so pressing at least. communists should always be the first ones to help those oppressed by feudal 'traditions'. and i believe the various communist organisations have indeed been working with the dalit groups in india and dalit are strongly represented in the parties' support base. organisation can be the only way to achieve anything, organisational alliaces with communists and these kinds of movements are only beneficial to the larger struggle.
i can't say 'how'. this is something that should, or rather has to be answered by those people who are in the places where this struggle is taking place. they are the ones to define the correct approach, and this approach can only be determined in the struggle.
"We shall not have succeeded in demolishing everything unless we demolish the ruins as well. But the only way I can see of doing that is to use them to put up a lot of fine, well-designed buildings." - Alfred Jarry