"The Indian child is also wearing a sweater."
Translation:Az indiai gyereken pulóver is van.
In general, there seems to be an issue accepting "viselni" for "to wear" across many of these examples. "Az indiai gyerek is pulovert visel" is perfectly fine, as is "visel" in several other contexts. I have consistently reported this, but felt it deserved a comment as it is so widespread.
Yes, it is grammatically correct. To be certain, one would need to know the intended context, as the English sentence has some ambiguity. The official translation suggests that the Indian child wears a sweater (in addition to trousers and a shirt, for example), whereas your translation suggests that the Indian child wears a sweater (as does the Chinese child and the Japanese child).
also = "szintén", too = "is", therefore "Az indiai gyerek szintén pulóvert visel" is a more elegant solution.
I wish that Duolingo would be more clear about the context around the Hungarian sentences. Without it, I can't always tell where I should put "is", and then it tells me I got it wrong...