The Clinical Trials Registry - India (CTRI), an online system (www.ctri.nic.in) for the registration of clinical trials being conducted in India, has its secretariat at the National Institute of Medical Statistics of the Indian Council of Medical Research in New Delhi. The primary objective of the CTRI is to ensure that all clinical trials conducted in India are registered in order to bring transparency, accountability and access to clinical trials.

The availability of multiple data sources and new methods of estimation resulted in a more accurate estimate of the HIV population in India in 2006. A critical review of the data and methods used in the past and current estimation processes is offered in this article.