Tear gas was released by accident on a busy road in Central on Hong Kong Island after four canisters fell from a police van on Wednesday night.

At 9pm, a police van of the emergency unit from Hong Kong Island Police District was driving along Connaught Road in Central heading to Admiralty when the incident took place, news website HK01.com reported.

As the vehicle drove past City Hall, a box containing four tear gas canisters fell out. It was understood that a Mercedes Benz which was following the police van drove over one of the canisters, leading to gas being released. The female driver of the Mercedes Benz immediately stopped her car and got out, while passers-by reported the case to the police.

Officers arrived and cordoned off the area. Officers from explosive ordnance disposal bureau were deployed. No one was injured.

Officers collected the damaged canister, which was caught underneath the private car, for further investigation.

The lock on the back door of the police van was faulty, Apple Daily reported.