Panic buttons are to be made mandatory on India’s public buses “to ensure the safety of women”, the transport minister has said, more than three years after the fatal gang rape of a student on a bus in Delhi.

The government said a series of measures designed to curb sexual violence against women would become law on 2 June.

“To ensure the safety of women after the unfortunate incident, we have decided to make it mandatory for public transport buses to install emergency panic buttons, CCTV cameras and GPS-enabled vehicle tracking devices,” Nitin Gadkari told reporters in New Delhi.

The “unfortunate incident” to which Gadkari was referring was the brutal attack on a woman in December 2012 as she returned home from the cinema. The assault triggered outrage and mass protests across India, leading to an overhaul of its rape laws, but high numbers of assaults persist.

The state of Rajasthan is pioneering trials of the new measures on 20 of its vehicles. Panic buttons are placed above the front doors which, when pressed, send an emergency message to a police control room that can then view live footage of the bus interior.

Gadkari said all public buses would have to be remodelled the same way, while manufacturers must ensure new buses come equipped with the facilities.

The government’s latest measure to prevent sex attacks follows its announcement last month that all mobile phones sold in India would have to have a panic button from the start of 2017. The button would allow users to call emergency services by pressing a single key on their phone.