A recent announcement released by the Consular Chief Mr. Michael Yoder at U.S. Consulate, Hyderabad and Mr. Bryan Dalton at U.S. Consulate, Chennai indicate that applicant(s) appearing for a non-immigrant visa interview from June 20, 2011 and June 30, 2011 at U.S. Consulate in Hyderabad and Chennai respectively will be allowed to enter the consulate only 15 minutes prior to their visa interview. Applicants arriving earlier than 15 minutes will be instructed to leave and return closer to their respective scheduled time for visa interview. This change will drastically reduce the wait time outside the consulate and avoid longer queues in the view of upcoming monsoon. The change is expected to expedite the registration and security procedures prior to the visa interview and provide better experience for applicants.

This announcement can be found here for Hyderabad and here for Chennai.