I am a US citizen currently in India needing a tourist visa to visit China on the 18th of March.

You may just apply for the China Tourist visa from the China Visa Application Service Center in New Delhi. The documents to be prepared are:
1. Your passport with more than 6 months validity left and at least two blank pages attached wirh a recent-taken passport photo;
2. A ful-filled China visa application form with genuine information;
3. Sufficient fund to cover yoru stay in China;
4. return air ticket;
5. Covering letter from applicant’s company or office;
6. Photocopy of personal data page of your passport;
7. Photo copy of your residence permit in India (it should be with at least 6 months validity)

You have enough time to apply for the visa, since the application takes 4 working days normally, and there is express service of the next working day collection.