Here is the LINK. This link give you information on technicalities such as service of process etc. Here is an excerpt.
Summary: Judicial assistance between the United States and India is governed by the Vienna Convention on Consular Relations (VCCR), 21 UST 77, TIAS 6820, 596 U.N.T.S. 261, to which the United States and India are parties and the bilateral Joint Secretary (Security), Ministry of Home Affairs, Treaty Doc. 107-3, 107th Cong., 2d Sess.
Service of Process: India is not a party to the Hague Convention on the Service Abroad of Judicial and Extra Judicial Documents in Civil and Commercial Matters or the Inter-American Convention on Letters Rogatory and Additional Protocol. If service of process from the United States is attempted in India by certain methods detailed in Rule 4 of the Federal Rules of Civil Procedure, such as service by mail; or service by a local agent such as a local attorney or service by publication is effected, that may not constitute service of process under Indian law. See our general Service of Process guidance. This may be important if eventual enforcement of a judgment in India is foreseen. Service may also be attempted in India pursuant to a letter rogatory, transmitted through the diplomatic channel to the Indian Ministry of External Affairs. See our guidance on preparation of letters rogatory. Letters rogatory for service of process should be transmitted to the U.S. Department of State, Bureau of Consular Affairs, Overseas Citizens Services, Office of American Citizens Services and Crisis Management, Near East and South Central Asia Division, CA/OCS/ACS/NESCA. Mailing address: SA-29, 4th Floor, 2201 C Street N.W., Washington, D.C. 20520. Express mail address: 2100 Pennsylvania Avenue N.W., Washington, D.C. 20037.See also our Service Under the Foreign Sovereign Immunities Act (FSIA) feature and FSIA Checklist for questions about service on a foreign state, agency or instrumentality.