Since August, the police have been summoning 10-15 people every day and checking their phones for social media messages. For many people across India, it seemed like another instance of official overreach when 28-year-old researcher Lois Sofia was arrested on September 3 for shouting an anti-Bharatiya Janata Party slogan at the party’s Tamil Nadu president after the plane on which they both were travelling landed at Thoothukudi airport. But to many in the coastal city, this was only the latest step in a campaign by the police to avert the possibility of protests against the city’s now-shuttered Sterlite Copper plant from flaring up again.