I am an Indian working in H1B visa in US. I am planning a trip to spain from India in the month of December. Since my return tickets would be booked from India, can I apply for my Schengen visa in US? I plan to apply for it in November.
Is the US H1B visa still valid through your whole trip, and do you intend to return to USA after the trip?
If both answers are "yes", then you should certainly apply for the visa in the US. It doesn't matter where you go after you leave Schengen - you don't need to go to USA directly. However it does matter that US is your current place of residence if you apply for the visa there, and for this it is important that your H1B visa remains valid. I would also suggest taking your itinerary from India to US with you for the interview, so you can show that you'd return to USA before your visa expires, as this might make your case stronger (if you're returning to USA you're much less likely to overstay).