Smart cities: Big Data's watching you

City streets are becoming a valuable source of big data, so should we care who is gathering it and how it is being used?

In Shenzhen in China, the authorities are using video footage and facial recognition technology to reward or punish citizens' good or bad behaviour - such as littering or running red lights - via "social credit" systems.

Meanwhile in the Canadian city of Toronto, a new waterfront redevelopment is introducing similar sensors and smart tech from Google subsidiary Sidewalk Labs. But does this just represent another data bonanza for the tech giant at the expense of people's privacy?

Jane Wakefield speaks to Sidewalk Labs' head of urban systems Rit Aggarwala, local activist Julie Beddoes, as well as tech consultant Charles Reed Anderson,

(Picture: CCTV security camera front of a city office building; Credit: nunawwoofy/Getty Images)