You can get a passport in as little as one day from the nearest passport agency if you make an appointment sufficiently in advance and show up with your certificate of naturalization, photos, completed application form and fees along with proof of urgency (travel tickets or itinerary).
If you once held Indian citizenship, getting an Indian visa can take 1-3 weeks since you must first obtain a surrender certificate and get your Indian passport canceled. If there is a true life and death emergency, you can contact the Indian consular official and try to get your visa application expedited.
