India will remain under lockdown till May 18, the government announced today, tacking on a second extension to the full lockdown announced by Prime Minister Narendra Modi originally on March 25. In containment zones which are high-risk areas, the government's Aarogya Setu app will be mandatory. The app evaluates users' risk of infection based on location, and their medical and travel history. It uses Bluetooth and location services to trace a user's contacts. Nobody can move in or out of containment zones except for medical emergencies, and for maintaining supply of essential goods and services.