Disease surveillance in India is a cornerstone of pandemic preparedness and response, aimed at the early detection, monitoring, and control of infectious diseases. Surveillance activities involve the systematic collection, analysis, interpretation, and dissemination of health-related data to guide timely public health interventions. India has significantly strengthened its surveillance systems over the years, especially after experiences with outbreaks such as SARS, H1N1 influenza, Nipah virus, COVID-19, and recurring vector-borne diseases. The Integrated Disease Surveillance Programme (IDSP), launched by the Ministry of Health and Family Welfare in 2004, serves as the primary disease surveillance system in India. It collects weekly data on epidemic-prone diseases from health institutions across districts and states. The programme follows syndromic, presumptive, and laboratory-confirmed surveillance, enabling early identification of unusual disease patterns. District Surveillance Units and State Surveillance Units analyze data and initiate rapid response measures whenever outbreaks are suspected. The Integrated Health Information Platform (IHIP) has modernized surveillance by replacing paper-based reporting with a real-time, web-enabled digital platform. It facilitates case-based surveillance, geospatial mapping, and immediate reporting of priority diseases. The platform enables faster detection of outbreaks and supports evidence-based decision-making. Laboratory surveillance forms another major component. India has developed an extensive laboratory network under the Indian Council of Medical Research (ICMR), National Centre for Disease Control (NCDC), National Institute of Virology (NIV), and other