This photo, taken on July 20, 2014, shows press-button emergency window breakers that have been installed on the operation panel of a city bus in Guangzhou, South China's Guangdong province. Safety concerns on public buses have grown recently after a man set a Guangzhou bus on fire to vent his frustration over incurred gambling debts on July 15. The resulting explosion killed two people and injured 33 others. [Photo/Xinhua]?

The first batch of 70 buses installed with press-button emergency window breakers have begun operating in southern Chinese metropolis of Guangzhou, capital of Guangdong province, recently.

When engaged, the emergency window breakers will blast the bus' glass windows open in a way so as not to injury the vehicle's occupants.

The mechanism reportedly takes between 0.1 and 0.3 of a second to bust open the windows.

Safety concerns on public buses have grown recently after a man set a Guangzhou bus on fire to vent his frustration over incurred gambling debts on July 15. The resulting explosion killed two people and injured 33 others.